Doctors should face a potential bill of £131,000 if they quit the NHS soon after completing their training, a report suggests.
Student medics should be made to take out loans to cover their training that would be paid back by the health service as long as they remained working within it under proposals drawn up by Civitas.
The move would allow restrictions limiting medical school places to around 6,000 a year to be lifted and help end the dependency on overseas doctors to plug "severe" staff shortages, the think-tank said.
Its report found the UK spends up to £12 million a year training international medical students who are free to leave the UK at the end of their course.
Edmund Stubbs, Civitas healthcare researcher, said: "The only way to solve the current medical staffing crisis is to find a way to train more medics in this country.
"What we need is a far larger pool of medics from which we can produce a stable, permanent workforce. It is also imperative we ensure that doctors continue to work for the NHS after the UK taxpayer has made such a major investment in their training."
The report claims thousands of newly-trained doctors swiftly leave the NHS to work for agencies, private providers or for posts in other countries.
Overall, 8,343 doctors applied for approval to practise in the UK in 2014 while the number of commissioned medical school places in the same year was only 6,071.
Staff shortages are set to increase amid growing pressures on services and the expected retirement of around 13,500 consultants and GPs in the next five years.
Around 9,400 new posts must be created between 2015 and 2019 to meet projected demand, the report warns.
Under the proposals, the NHS would repay the 30-year loans at a rate of around £4,380 a year but doctors would have to repay the outstanding debt if they left the service before it was cleared.
Mr Stubbs added: "The NHS, faced with a staffing crisis and serious underfunding, cannot reasonably be expected to fund the training of medics who have no desire to work for the organisation.
"Those medics who want to work in the private sector or abroad after qualifying might, in the light of the proposed scheme, be encouraged to consider undertaking their medical education overseas or even in the rapidly expanding private medical university sector.
"It is possible that some private or overseas healthcare employers might be prepared to repay student loans on behalf of their employees as an incentive to work for their enterprises.
"The fact that we fully fund the placements of international students is alarming. The money saved from the NHS no longer paying clinical training placement fees on behalf of such students could fund the training of many more UK medics."