Plans for patients to opt for healthcare in any EU member state if they wish will be unveiled today.
The new "single market" in medical treatment is partly a response to a European legal ruling last year which backed the case of 75-year old Briton Yvonne Watts, who paid £3,900 for a hip replacement in France because she was not prepared to wait a year for an operation in the UK.
The NHS refused to reimburse her but the EU judges said she was entitled to shop around in the EU because of the "undue delay" in her treatment prospects in Britain.
If approved by EU ministers, the European Commission proposals would oblige national health systems in the 27 EU countries to provide equivalent hospital facilities to those patients would be offered in their own countries.
Some Labour MPs claim so-called EU "health tourism" could undermine the NHS, but Tories welcomed the move as freedom for NHS patients to express their views about the service.
Conservative health spokesman in the European Parliament and former UK health minister John Bowis commented: "With ever-growing concerns over the spread of hospital infections like C.difficile and MRSA, we will doubtless see people voting with their feet on the Government's handling of the NHS."
Labour MEP Linda McAvan, who is a member of the European Parliament's Public Health Committee, said: "For many years, individual people have been going to the European Court of Justice to establish their rights to treatment in another country.
"Legislation in this area will be helpful if it provides clarity to the public about the rules which apply when seeking treatment abroad and if it helps health systems to manage requests for treatment in other EU countries."
She added: "While cross-border healthcare might be useful, it is the NHS that must decide what treatment it pays for if UK patients choose to travel abroad for care.
"Case law already exists from the European Court of Justice which allows patients who wish to receive care abroad to do so, and this has not resulted in a large number of people wanting to go abroad for treatment or a large number of other EU nationals seeking treatment in the UK.
"The priority for the vast majority of NHS patients is high-quality healthcare received close to their homes."
Fellow Labour MEP Arlene McCarthy said the Commission plans should not raise false expectations that patients can access healthcare in Europe "anywhere at any cost".
She added: "The right to access healthcare in other EU countries must not undermine the integrity and financing of the NHS and it mustn't disadvantage those who don't have the cash to pay upfront for treatment."
Patients could be travelling routinely abroad for health treatment if they wish by 2010, although the proposals will run into some opposition as they are negotiated by EU ministers.
A European Commission statement said primary responsibility for providing healthcare rested with national authorities: "In most cases patients will have the care they seek from their domestic health system, without needing to consider healthcare abroad."
But it went on: "However, in some instances healthcare may be better provided in another member state - for rare conditions or specialised treatments for example, or in the case of border regions where the nearest appropriate facility may be in another country.
"Therefore the Commission has developed a legal instrument to help realise the potential of the European dimension for healthcare."
The aim was "safe, efficient, high-quality" cross-border treatment.