Doctors' leaders have criticised the continuing reliance on medical staff from developing countries to fill NHS vacancies.
British Medical Association (BMA) chairman James Johnson said taking much-needed staff from African nations is morally indefensible.
The government's tougher code to prevent the active recruitment of such workers does not stop those who volunteer to come to the UK, he said.
Last year two-thirds of newly-registered doctors, and more than 40% of nurses, came from abroad.
And, over the last six years, nearly 16,000 African nurses have registered to work in the UK.
The government recently introduced a tougher code of practice to stop the active recruitment of the developing world's health workers. But the BMA says this move does not stop those who volunteer to come to Britain in search of better salaries and conditions.
The Department of Health said that the NHS does not actively recruit from any country that does not wish to be recruited from.