UNLIKE most snakes, which usually only attack people if they are taken by surprise, new research has found that the Australian mulga snake has been striking at people while they sleep.

The nightmarish conclusion was reached after a study examined 27 victims of the snake and found that seven of them had been bitten in their sleep between the hours of midnight and 5am, Live Science reports.

The majority of people who had been bitten by a mulga snake had initiated contact – one had been playing with the snake in the garden, and another had been feeding a pet, but of the ten people who were attacked without provocation, seven had been bitten while they slept.

Researchers said that the number of bites "is noteworthy since it represents 70 per cent of identified cases involving bites without intentional contact, and suggests that bites sustained during sleep may be more common than previously reported".

The mulga snake (Pseudechis australis) is Australia's largest venomous terrestrial snake. It is capable of inflicting severe pain and bites can occasionally be fatal, although no deaths have been recorded in the last 40 years.

Researchers said it is unclear why the snakes had bitten their victims in their sleep. In one case they said "the snake may have been attracted to the victim's body heat". In another, it was felt that the snake had been startled when searching for food.

The findings were first published in the online journal Toxicon.