Olympic gold medallist Usain Bolt has expressed his "shock" in discovering that Paralympic champion Oscar Pistorius has been charged with murder.

The 26-year-old double amputee sprinter has been charged with the premeditated killing of his model girlfriend Reeva Steenkamp by shooting at her four times through a bathroom door at his home in Pretoria, South Africa.

"When I heard [about the murder], I was like, 'What? Who? The amputee guy?'," Bolt told CNN. "I was asking all sorts of questions because I was thinking, 'This can't be the same guy that I've seen and I know.'

"I still can't process it really. As far as I'm concerned, I'm just listening out and listening to the news. I'm still in shock."

Pistorius is currently awaiting a decision as to whether he will be granted bail at a court hearing in Pretoria.