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The chief secretary to the Treasury was speaking in regard to Starbucks, which last week said it would voluntarily pay more UK corporation tax.
Mr Alexander told the BBC's Andrew Marr Show that the government was continuing efforts to tackle tax avoidance.
He said this work was taking place both in the UK and abroad.
"Taxation for big companies, or for anyone in society, can't be, and mustn't be, a voluntary arrangement," said Mr Alexander.
"Thinking of the tax system as if it is like the church plate going around on a Sunday morning is completely the wrong way to think about it."
He added: "Paying tax is not a voluntary choice, it is not something you can just chose to do willy nilly because you think it will please your customers, it is an obligation."
Coffee chain Starbucks announced on Thursday of last week that it would pay about £20m in UK corporation tax [tax on its profits] over the next two years, following a public outcry over how little it pays.
The company has paid just £8.6m in corporation tax in its 14 years of trading in the UK, and nothing in the last three years, despite UK sales of nearly £400m in 2011.
Two other multinational companies which have also been criticised for paying too little corporation tax - Amazon and Google - both said they would not be following Starbucks' voluntary contribution lead.
London Mayor Boris Johnson on Sunday defended companies, such as Starbucks, for seeking to minimise the level of tax they paid in the UK.
In an interview on Sky News, he said: "Imagine that you are the corporate finance director of one of these companies.
"Your job is to look at the law as it stands. Your fiduciary duty to your shareholders is to minimise your tax exposure."
Mr Johnson added that Starbucks should be praised for announcing that going forward it would voluntarily pay UK corporation tax.
"Now that Starbucks has stepped up to the plate and announced they are going to be making this payment I think rather than everybody sneering at them, people should welcome that," he said.
"My point is it is a bit unfair to bash the companies and then sneer at them when they try to do good."
Mr Alexander also reiterated that the government had announced in last week's Autumn Statement that it was giving HM Revenue & Customs more funds to tackle tax avoidance and evasion.
He said the aim was to get an additional £9bn in tax revenues per year.
Mr Alexander added that the government, together with Germany and France, was putting additional funds into the Organisation for Economic Co-operation and Development, to aid work on establishing global agreements to prevent companies avoiding tax by moving profits from one country to another with a lower tax rate.
"At a time of austerity, everyone has an obligation to to play by the tax rules," he added.
Danny Alexander has told multinational firms that paying tax is an obligation, not "a voluntary choice" they can make to please their customers.

In a world where how fast you can assimilate and analyse data, then act on it, makes the difference between profit and loss, computing speed is key.
This is why banks, insurance firms and hedge funds invest millions on technology to give them an edge when trading and to offset human error.
Quantum computers, that owe more to quantum mechanics than electronics, promise to be exponentially more powerful than traditional computers, holding out the tantalising prospect of near-perfect trading strategies and highly accurate forecasting and risk assessments.
"Financial services is a data-rich environment," says Kevin Hanley, director of design at the Royal Bank of Scotland (RBS). "Time is money and the ability to process data fast could have a huge potential benefit for our customers."
Classical computing relies on binary digits or bits - ones and zeros representing on/off, true/false states.
Quantum computing, on the other hand, features qubits, which can be both 0 or 1 at the same time - a state known as superposition. It all goes back to Schrodinger's cat, but that's another story....
Subatomic particles such as electrons, photons or ions can be made to behave in this mysterious way.
And because of this flexibility, qubits can do a lot more - a quantum computer could theoretically carry out trillions of calculations per second.
But these computers aren't easy to build or operate. Quantum processors from one of the leading manufacturers in this field -  D-Wave -  need to be cooled to just above absolute zero (-273.15C). They also need to be free from any electromagnetic interference.
This makes them bulky and costly; D-Wave's computers cost about $10m-15m.
Ironically they're also a bit limited in the kinds of calculations they can currently do, and many observers are still sceptical about how fast they really are.
So it's fair to say we're still at the very early stages of quantum computing.
Goldman Sachs, RBS, Guggenheim Partners and Commonwealth Bank of Australia have all invested in quantum computing, with the aim of stealing a march on their competitors.
"This is interesting to the financial world because if you can find an algorithmic advantage to solve a problem, that can give you a great competitive advantage," says Colin Williams, director of business development for D-Wave.
Google, Nasa, Lockheed Martin, the US Department of Energy and the University of Southern California have all used D-Wave's systems so far.
Other tech companies, such as Cambridge Quantum Computing, QxBranch and Rigetti, are also rushing to develop the hardware and software needed to make quantum computing a reality.
Quantum computers could solve problems in a day that would take classical computers thousands of years to solve.
So in the world of investment, they could consider millions of different global investment scenarios and calculate which ones have the best chance of success over the long-term.
"We can build an optimal portfolio today, but tomorrow it won't be optimal and needs to be rebalanced, which is expensive," says Marcos Lopez de Prado, a senior managing director at Guggenheim Partners.
Quantum computers could, in theory, give investment firms much better visibility over the longer-term to make more accurate predictions and reduce this need to tinker with their portfolios, saving costs and possibly boosting profits.
"If you can predict the US dollar/Swiss franc exchange rate a tenth of a cent more reliably, then the value isn't in the computer, it's in the cost saving," says Mr Williams.
Better forecasting could also reduce the prevalence of high-frequency trading, which has been accused of creating market volatility.
High-frequency traders have also been blamed for raising the costs of trading for ordinary investors by swooping into purchases nanoseconds before an interested party and reselling the stocks at a higher price.
So how soon will quantum computers be readily available?
D-Wave's Mr Williams reckons businesses will have access to quantum computing functionality by 2018, whereas RBS's Mr Hanley thinks it will be "five to 10 years before quantum computing comes of age".
But this isn't stopping financial institutions getting excited.
Blu Putnam, chief economist for the CME group - a US-based derivatives market - says quantum computing has led to a "mind-set change" where financial services "now seek out the nearly impossible to solve problems" in asset and risk management.
Before then, there is a lot of preparation to do.
Quantum computers can't be interrogated in the same way as traditional computers. The algorithms - sets of complex mathematical rules - used for classical computing need to be reworked to fit into the quantum system.
And finding and training computer scientists to understand and use these systems effectively is another big challenge for the financial services industry.
But Mr Hanley says: "Rather than observe these changes from a distance or be last in the queue, I'd rather be at the front and have a seat at the board."
Quantum computing may offer potential benefits to the financial services industry, but it also poses risks.
Banks rely on encryption to keep their transactions and customer data secure. This involves scrambling and unscrambling data using keys made of very large numbers - tens, if not hundreds, of digits long.
A hacker would have to find the right key by trial and error and test it in order to unlock the data - a process that could take hundreds of years even with the most powerful of today's supercomputers.
But quantum computers could crack the code with relative ease, potentially undermining the security of the entire global financial services industry.
Such a possibility leads Mr Lopez de Prado to fear that governments might outlaw quantum computers entirely.
"Governments could say they should be banned because otherwise there would be no secrets, but they can't be un-invented.
"We need a new mathematical breakthrough that creates an unbreakable encryption," he says.
Cryptographers are busy working on new algorithms to block attacks from future quantum computers and many believe this will be possible.
But the industry needs this breakthrough fast. The processing power of quantum computing is growing with each generation.
Follow Technology of Business editor @matthew_wall on Twitter.
Superfast quantum computers could transform the world of finance, advocates say.

Andrew McVicar, 33, of Dewsgreen, Basildon, Essex, was charged with robbery in The Drive, Hullbridge, on 19 March.
Timothy Smith died two days later from head injuries.
Mr McVicar appeared at Chelmsford Magistrates' Court on Saturday and was remanded in custody. He will appear at the city's crown court on 27 April.
He was arrested on Friday morning in north Lanarkshire.

A man has been charged in connection with a robbery in which a 57-year-old man suffered fatal injuries.

