A South African tour guide has denied responsibility for the death of his American client who was mauled to death by a lion while they drove through a game park near Johannesburg.

Pierre Potgieter, 66, was badly injured as he tried to save the woman when the lion leapt through the open window of his car.

He accused an employee at the privately-run Lion Park of failing to help after the victim, named as Katherine Chappell, 29, suffered severe injuries to her neck in the attack on Monday.

"The tourist had a camera and, of her own accord, rolled down the passenger window in order to take photographs. A lion then attacked (her) through the open window," said a statement from Potgieter's company, Kalabash Tours.

"(He) tried to fend the lioness off and in the process sustained injuries to his arm.

"When the lion retreated, Mr Potgieter saw that the tourist had sustained extremely serious injuries. She was bleeding profusely from her neck."

The statement, released late Wednesday, said Potgieter tried to save her life but that a park employee who arrived on the scene was "reluctant" to help give first aid to Chappell.

"The ambulance only arrived some time thereafter. For Mr Potgieter, this felt like a very long time," it added.

US embassy officials declined to identify the victim out of respect for her family, but local and international media named her as Katherine Chappell, a video effects editor based in Canada who had worked on the hit TV series "Game of Thrones".

Potgieter was taken to hospital with severe arm injuries and also suffered an apparent heart attack during the incident.

The park, which remains open, has defended itself, saying that visitors are instructed to keep windows closed at all times, and that the ambulance arrived soon after the attack.

The lion has been put in an enclosure not open to the public.

It was the latest attack at the park, which is popular with both locals and foreigners.

In March, an Australian tourist was injured by a lion after driving through the park with his car windows open.

Two days later, a 13-year-old from a nearby slum was attacked by a cheetah while riding a bicycle through the grounds.

In December 2013, former South African franchise rugby player Brett Tucker and his family were attacked by a lion and his father reportedly suffered minor injuries.