By Nick Triggle
Health reporter, BBC News
Concerns were raised about the care of wounded soldiers
The military's medical arm is under severe strain because of a huge shortage of doctors, unions say.
A third of the 768 doctor posts in the armed forces are currently unfilled with the worst shortages in some of the most critical areas like anaesthetics.
The British Medical Association said the problem meant doctors were risking burn-out because they were having to return to the front-line too quickly.
The government said it was trying to rectify the shortfall.
While the pressure on military doctors has been relieved slightly by the withdrawal from Iraq, the revelations still raise concerns amid the mounting death toll in Afghanistan.
Military doctors spend their time being shifted between NHS work and deployments with the armed forces.
Normally they will only be deployed once every 12 to 18 months, but the BMA said some medics are being sent out every six months.
This includes working in field hospitals and close to the front-line in places such as Afghanistan as well as being based on war ships.
Overall, the Ministry of Defence had 528 trained doctors at last count. For anaesthetists, 53 were in place out of a requirement of 95, while none of the three neurosurgery posts were filled.
The shortfall has also hit nurses with one in 10 posts unfilled, rising to four in 10 and five in 10 for emergency care and intensive therapy nurses respectively.
The situation has got so bad that in recent months in the main field hospital in Helmand, Afghanistan, 70% of staff have been reservists, the BMA said.
Reservists basically acts as emergency back-up and as such their skills and preparedness may not be as up-to-date as those employed full-time by the Ministry of Defence.
Dr Brendan McKeating, chairman of the BMA's armed forces committee, who is now on the reservist list but served during the first Gulf War, said the shortfall was "a long-standing problem".
He said because of the new contracts NHS doctors have received in recent years, pay of military doctors lagged behind the health service by between 5% and 10% depending on speciality.
"We believe military doctors should be getting more to reflect the dangerous and unpredictable nature of the job.
"But it is not just about pay. We are also in the situation where doctors are being sent to the front-line more frequently to fill gaps. Morale is suffering."
However, he stopped short of saying lives were being put at risk as doctors were always willing to go that extra mile to ensure services were running properly.
He also acknowledged the Ministry of Defence also used contractors to fill any gaps.
The Ministry of Defence admitted there were problems, but said it was trying to improve recruitment and retention.
A spokesman said: "The Defence Medical Services have met all the operational requirements placed on them.
"We acknowledge that manpower shortages remain a problem, especially in some key specialties.
"We are taking active steps to address the shortfalls through a range of measures including the payment of 'golden hellos' to direct entrants in specialist areas and ensuring pay remains in line with the NHS."