An investigation into how well the private healthcare market is working is being planned by the Office of Fair Trading (OFT).
It will aim to formally launch its investigation in spring next year to examine the nature of competition in the market.
The OFT said its preliminary research had raised questions about whether the market was working well for private patients, the BBC reports.
The private healthcare market is worth £5.5bn and is of growing importance due to an ageing population, improved medical outcomes and higher life expectancy, the OFT says.
It added it was of growing importance to the NHS because of government initiatives that allow NHS patients to seek treatment from private healthcare providers in certain circumstances.
Sonya Branch, OFT senior director of services and public markets, says: "We are keen to focus on whether patients and buyers of private healthcare, including the NHS, are getting the full benefit of choice and competition."
The OFT will be speaking to providers, patients and government to make sure it is focussed on the correct issues.