Gaza hospitals are reduced to practicing "medieval medicine", a British surgeon recently returned from the bombarded Palestinian territory said on Monday.

"It's absolutely true to describe it as medieval medicine. It is what you would hear about or read about what would be happening in Europe maybe 300, 400 years ago," Dr Khaled Dawas, head of gastrointestinal surgery at University College London Hospitals, told AFP in an interview.

Dawas described dire conditions in Gaza, with medical staff operating virtually without supplies, power supplies intermittent and patients lying on the floor.

He returned at the end of April from his two-week stint to help overstretched Palestinian hospital surgeons -- his second wartime stay there, following one in January.

"By April they were seeing this constant, constant volume of dying and dead bodies coming into the hospitals and any human wouldn't be able to tolerate it," he said.

"They carry on working, but you can see the effect of that. They're all extremely burdened by what they're doing."