BERLIN (AFP) - South African Paralympic star Oscar Pistorius, who is facing trial for the shooting dead of his girlfriend at his home in February, suffers from serious psychological problems, his manager said in an interview on Monday.

"Oscar sleeps poorly. He eats poorly. There are days when he's okay but other days it's terrible," Mr Peet van Zyl told the German weekly Der Spiegel on the eve of a new pre-trial hearing for Pistorius in Pretoria.

"When you talk to him, of course he listens but I don't reach him, he's not there. He cries a lot," Mr Van Zyl said.

Pistorius, 26, is free on bail of one million rand (S$126,000) and living with his uncle in the South African capital Pretoria where his manager visits him once a week.

"He sees a psychologist two or three times a week," Mr Van Zyl said. "She is strict with him. When I see him after a session he always seems completely gutted."

Pistorius is due to appear on Tuesday in a Pretoria court for a pre-trial hearing but both the defence and prosecution expect the case to be swiftly adjourned while detectives pursue their investigation.

A date for the full trial has not been set.

The athlete nicknamed the "Blade Runner" for his trademark carbon-fibre prosthetic limbs claims he shot his 29-year-old lover Reeva Steenkamp through a locked bathroom door in the early hours of Feb 14 after mistaking her for an intruder.

The prosecution argues it was premeditated murder, a crime that carries a maximum sentence of life in prison.

Pistorius became an inspiration to millions as the first double amputee to compete against able-bodied athletes at the Olympics last year.