In total 793,642 cars were built between January and June, up by 0.3% on a year ago, The Society of Motor Manufacturers and Traders (SMMT) said.
It marks the best half-year since 2008, and means three cars a minute were made in the period, the SMMT said.
In June, the number of cars made rose 5.4% on a year ago, with demand for exports driving the increase.
In contrast, demand for cars in the UK fell 7.1%.
Overall, production volumes have risen by more than 50% since 2009, the SMMT said.
It said new models and "significant" planned investments meant it expected the industry to continue to grow.
SMMT chief executive Mike Hawes said the figures showed that the UK's investment in high-tech manufacturing had paid off.
"This success has been built on significant industry investment and has also relied on a positive relationship with government, essential if the industry is to maintain its international competitiveness," he added.
UK car production hit a seven-year high in the first half of the year, the industry's trade body has said.