Healthy people who are not considered to be "at risk" of contracting the flu virus should be banned from having private vaccinations, the chairman of the Royal College of GPs has said.
Dr Clare Gerada said healthy individuals buying the flu jab from pharmacies have contributed to shortages in the NHS and left those at greatest risk vulnerable to infection.
Some GPs in England have reported running out of stocks of the vaccine, as thousands try to protect themselves against the winter outbreak that has killed 50 and left hundreds requiring critical care.
Dr Gerada said: "People who are not in the at-risk groups are getting (private) vaccinations, leaving less supply for us. If that's going to happen again then the Government needs to stop it and think because that will affect the delicate balance that we have."
Dr Gerada called for a study into how many healthy people had privately purchased the jab to gauge whether there should be a law banning the practice. Many pharmacies have offered the jab for about £15, according to reports.
GPs in England and Wales have faced criticism for not ordering enough of the flu vaccine to protect those considered at-risk, such as people aged 65 and over and pregnant women.
A spokesman for the Department of Health said: "Community pharmacies are working with GPs to ensure that at-risk groups are vaccinated, as far as is possible, with limited remaining stock. Pharmacies are private businesses and we are not able to prevent them from selling the vaccine commercially."
On Monday Health Secretary Andrew Lansley was accused of being poorly-prepared for the current flu outbreak.
Labour said the Health Secretary made a "serious misjudgment" by axing the autumn advertising campaign to encourage vaccination take-up. However, Mr Lansley said the NHS was "well-prepared" for the outbreak.
The number of deaths this winter from flu was currently 50, with 45 being associated with the H1N1 infection.