The Department of Health (DoH) has restated its intention British medical graduates are prioritised for training posts in the UK.
The DoH issued guidance last year that no international medical graduate (IMG) should be recruited if a candidate from the UK or European Economic Area (EEA) was available - but this was struck down by the Court of Appeal.
Ministers have now used the Home Office's points-based immigration system to restrict foreign doctors taking up NHS training posts.
Health secretary Alan Johnson said today it was "only right" measures should be taken if UK medical graduates cannot access specialist training because of a large number of applicants from outside Europe.
Under the previous system, training schools could not discriminate against the 16,000 foreign applicants from outside the EEA, but new conditions from the Home Office will seek to prohibit migrants taking up doctor training posts.
Migrants applying under Tier 1 (general) for highly skilled migrants can only be approved if they meet an identifiable skills shortage in the UK, but with an increase in UK medics and falling training places they are unlikely to be eligible.
Mr Johnson said: "Doctors from overseas have played an invaluable role in the NHS for many years and will continue to do so. They have helped us fill key shortage areas such as psychiatry, obstetrics and gynaecology, and paediatrics.
"But as the number of UK medical school graduates expands, there should be less need to rely on overseas doctors for these specialties."
It can cost up to £250,000 to train a UK medical student, while the creation of three new medical schools since 1997 means the system is moving towards self-sufficiency.
Moreover, the DoH is concerned migrant medics only tend to stay in the NHS an average of four years, depriving the health service of the skills it helped train.
The new Tier 1 (general) criteria takes effect from February 29th, replacing the highly skilled migrants programme, and is expected to impact on recruitment from 2009.
From February 29th, anyone from overseas already in the UK under the highly skilled migrant programme will have to re-apply under Tier 1 (general).
From April 1st 2008 this begins its international roll-out, with Indian migrants the first to apply for Tier 1 (general) from overseas.
Despite the move, the DoH concedes between 700 and 1,000 UK doctors will still be unable to secure an NHS training place in 2009 or beyond.
In the meantime, the DoH is appealing to the House of Lords to defend its original guidance, with a decision expected by May.
In September Gordon Brown promised "British jobs for British people" but the Conservatives warned he would be unable to enact this under existing legislation.