Margot Robbie punches Tarzan during sex scene

It was crucial to the director of the new Tarzan film that Margot Robbie's Jane was a modern woman, so he asked her to punch actor Alexander Skarsgard in a sex scene.

The Aussie star takes on the role of Jane in the early 20th century tale of a man raised by apes in the African jungle. She was the perfect fit for the role, according to director David Yates.

"If you enter the jungle with anybody, you want to go with Margot Robbie," Yates told Entertainment Weekly.

"She's practical, she's smart and she's resourceful.

"She can take care of herself."

Yates said the modern interpretation of the character was most apparent during a moment of passion, in which Jane punches Tarzan during sex.

"They're doing this love scene together, and I said, 'Just slap Alex [Skarsgard] while you're making love, just kind of give him a punch," Yates said.

"It was sort of an earthy, sensual moment of her enjoying sex with Alex."

Skarsgard, who plays Tarzan, said it was important the character of Jane was updated for the modern day.

Robbie's Jane would not be a damsel in distress, he said.

"It was very important that we didn't want it to feel archaic or dated where it's like, tough guy has to save the poor girl," the True Blood star said.

"You have to feel that she's strong and independent."