An elephant was put down in South Africa's Kruger National Park after it attacked and overturned a vehicle, ripping open a British woman's thigh with its tusk, the park said Tuesday.

The bull injured a couple, who had been filming it, after charging at their car in the mega-wildlife reserve on Monday.

"It suddenly stopped, turned around and rapidly walked towards the vehicle which was stationery at that time," the park said.

"The elephant charged at them, attacked the vehicle and flipped it over off the road into the thick bushes."

The couple was airlifted from the scene, stabilised, and then flown to a nearby hospital.

"The female tourist was seriously injured by one of the elephant's tasks which perforated and ripped open the back of her upper thigh," said the park.

The woman is a United Kingdom citizen. The man, who suffered minor injuries, is a South African living in the UK.

The bull was put down and was discovered to have been in musth, a condition that usually affects males once a year when testosterone levels, aggression and sexual activity increase.

The "abnormal behaviour" was also likely a result of an injury the elephant had suffered before the incident.

"Tourists are requested to always keep a safe distance at any animal sighting as they can be dangerous at times," said the park in a statement.