JOHANNESBURG (AFP) - Oscar Pistorius' trainer said on Monday he is shocked that the Olympic athlete is facing murder charges, describing him as a polite and humble man.

Jannie Brooks, who has trained the Blade Runner for more than a decade, said he knew nothing about Pistorius' personal or social life.

But he said the charges that he murdered his girlfriend, model Reeva Steenkamp, came like a bolt from the blue. "It was definitely a very very big shock for us, very sad," Brooks told AFP.

He said he has been training Pistorius since he was a teenager and saw nothing amiss about him. "All the time he trains here he is always very humble, very polite with all the people - so we never really experienced nothing in terms of .. bad or negative sign for more than 10 years."

Pistorius, who is being held at a Pretoria police station over the Valentine's Day murder, goes to court on Tuesday to seek bail.

The prosecution wants to charge him for pre-meditated murder.

The widespread shock at his arrest has become a measure of his stellar status in sport and beyond.

"A lot of people here and overseas still support him and so they will weigh what will happen (in court)," said Brooks.

The 26-year-old had both legs amputated below the knee when he was 11 months old because of a congenital condition that meant he was born without fibulae - lower leg bones. But he grew up to race non-disabled athletes on his custom-made carbon fibre blades.

Brooks told AFP last year that Pistorius "likes fast cars. Every time he comes here, he's got another car.

"He is just built for speed, because the cars have an amazing performance... that I think is his hobby."