The situation was revealed during an evidence session of the House of Commons public accounts committee, which was hearing evidence on patient safety last month.
NHS chief executive Sir Nigel Crisp said that, while the rate of adverse incidents reported by NHS bodies currently runs at about 60,000 a month, no similar information is gathered for private sector providers.
It means there is no systematic information on adverse incidents for GPs to provide to patients to help them choose between providers.
Labour committee member Jon Trickett, MP for Hemsworth in West Yorkshire, said it was 'profoundly unsatisfactory', adding that it demonstrated there was no level playing field between the NHS and the rest of the medical health sector.
The National Patient Safety Agency has statutory powers to collect information about accidents in the independent sector. However, it does not exercise them, the committee was told.
Mr Crisp admitted that he had no idea how many accidents occur in independent sector hospitals or treatment centres. Any information on this was gathered as agreed under contracts with individual organisations.