Oscar Pistorius has been filmed playing football in prison with a man reported to be an alleged gangster.

The former sprinter is serving a five year sentence at Kgosi Mampuru prison in Pretoria for shooting his girlfriend Reeva Steenkamp.

A new video has emerged of him enjoying a prison yard penalty shoot-out with Czech fugitive Radovan Krejcir, the Daily Mail reports.

The pair have reportedly struck up a friendship behind bars.

Pistorius, wearing grey shorts and a white t-shirt, appears to be dramatically slimmer than he was at his trial in the footage, which was reportedly shot by a fellow inmate.

The double amputee was convicted of negligent killing last year after admitting to shooting Steenkamp through the couple's bathroom door.