Dan Tan, also known as Tan Seet Eng, had been held indefinitely without trial since October 2013 but was released last week under a court order.
Police said his re-arrest on Tuesday was over "suspected involvement in criminal activities" and that investigations were ongoing
Mr Tan says he is innocent.
His lawyer, Hamidul Haq, told reporters on Wednesday that he was trying to find out exactly why he had been arrested.
"We are still finding out what the next steps are," he told the Associated Press. "We will want to try to see him to take instructions. I don't know if the police will allow that."
Mr Tan is wanted by several countries including Italy, but Singapore does not have extradition treaties with them.
He has been implicated by Interpol in fixing hundreds of sports events, mostly football matches, and is suspected of having fixed matches in Italy's Serie A and Serie B in 2011.
It has previously called the 51-year-old "the mastermind and leader of the world's most notorious match-fixing syndicate".
Mr Tan had been held under a law allowing for indefinite detention of suspected criminals without trial. Such detentions are reviewed every year.
But a judge ruled his detention was unlawful as he posed no threat to the public.
Fifa, football's world governing body, said at the time it was disappointed with the decision.
Singaporean police have rearrested Dan Tan, the man accused by Interpol of being the mastermind behind a global football match-fixing ring.