Hundreds of doctors spend months bogged down in red tape before they are able to take up GP or consultant posts, the doctors regulator has said.
The General Medical Council (GMC) said that each year it receives applications from 850 doctors who have not gone through conventional training programmes.
In order for these medics to get onto the specialist or GP registers - which is necessary to work in the NHS - they are required by law to submit more than 1,000 pages of evidence, which can take months to complete, the GMC said.
The regulator said the system is "is slow, bureaucratic and burdensome" which has an impact on the speed doctors can work in the health system.
In its submission to the Government's consultation on reforming health and care regulators, the GMC called for more flexibility to the regulation for doctors working in the UK.
The document states: "The legislative framework governing healthcare professional regulation is not fit for the needs of the public, professions, employers or wider health services in the 21st century."
Charlie Massey, chief executive of the General Medical Council, said there is an "acute" need for reform, adding: "Our ambition to innovate and act at pace is hampered by current legislation, which is far too prescriptive.
"Too often we know how we would like to regulate but we are unable to make changes because of the cumbersome process necessary to deliver them.
"For example, the current legislation forces us to pursue investigations that would be better dealt with in other ways.
"At the moment around 75% of our investigations close with no further action. This causes needless distress for both doctors and patients.
"It is also a waste of resources; we would like to put these to better use by supporting good practice and professionalism and preventing harm."