The chief executive of HealthEngine, the online GP booking business at the centre of a review-tampering controversy, has apologised for the company's actions and announced a sweeping review of its "aspirational review system".

Fairfax Media revealed exclusively on Sunday that 53 per cent of the 47,900 "positive" patient reviews on HealthEngine had been edited in some way, with many turned from tepid or negative to "positive customer feedback".

Chief executive of HealthEngine, Dr Marcus Tan, said the company only published positive reviews.

Initially, HealthEngine's head, Marcus Tan, defended the company's review policies, saying it published only positive reviews because it wanted to celebrate high-performing GP practices.

But in a letter published on HealthEngine's home page on Monday, Dr Tan, himself a GP, said the company did not mean to mislead readers and had realised it could do things better.