BERLIN - Fatal car crashes lay bare social tensions in two very different countries in upheaval, South Africa and Romania, in new movies in competition at the 63rd Berlin Film Festival.

Layla Fourie, a thriller about a single black mother in post-apartheid South Africa, and Child's Pose, centred on a wealthy son in Romania after communism, see both protagonists trying to pick up the pieces after deadly car accidents they caused.

Tired of working odd jobs, Layla is pleased to land a steady position at a casino that uses lie detector tests to vet potential employees.

But while en route with her young son from Johannesburg to her new place of employment, her car hits a white man on a dark road.

Layla tries to take him to hospital but he dies on her back seat and when she goes to tell the police what happened, she panics and races off to dispose of the body at a garbage dump.

She eventually meets her victim's wife and son and the film spotlights race-based fears and mistrust, as Layla wrestles with her guilt but is terrified about the potential consequences of confessing.

"It is a very violent society. Life is cheap, there's enormous poverty," said Terry Norton, a white South African who plays the victim's wife.

"Everybody thought that with reconciliation it was going to be this Rainbow Nation. It's not as simple as that.

"It's going to take time. I hope that we will come through.

"That's why I'm so grateful for this opportunity to be telling our stories with this film. It's a chance to make a positive contribution."

Johannesburg-born, Berlin-based director Pia Marais, who shows the white family living behind security bars and with fierce German Shepherds to ward off home invaders, said anxiety about crime only sharpened social stratification.

"I think that the new way of kind of barricading yourself behind high walls and electric fences, it's a new kind of apartheid, isn't it?" she told reporters after a pressscreening.

Child's Pose, by Calin Peter Netzer, got a warmer reception at the festival, with its own look at a young democracy breaking with the past.

Barbu is the scion of a wealthy family with high standing in Bucharest society.

His domineering mother Cornelia has a glittering birthday bash where the city's political and business elite come to raise a glass in her honour.

During the festivities, she gets word that Barbu has killed a teenager from a poor village.

She and her sister race to Barbu's side and begin dictating his police statement, making clear the young man will not spend a day in prison.

Cornelia orchestrates a campaign to bribe witnesses and officials and even tries to pay off the family of the victim to keep them from testifying against Barbu.

The son, however, has long felt suffocated by his force-of-nature mother and shows little gratitude for her efforts in a society where money has replaced party ties as the stock in trade.

Lead actress Luminita Gheorghiu said: "I don't think it's representative of the mothers in Romania, but it represents certain familial structures."