Paralympic champion Oscar Pistorius carried a gun with him "all the time" during a former relationship, a court has heard.

Samantha Taylor, who is a former girlfriend of Pistorius, has been giving evidence on day five of the sportsman's murder trial in Pretoria.

The 27-year-old is accused of murdering girlfriend Reeva Steenkamp, whom he shot dead through a bathroom door in his home on Valentine's Day last year.

While at the stand, Ms Taylor claimed that Pistorius had a gun with him at all times, and described an incident when he allegedly fired a shot out of a car's sunroof.

A court has heard that Pistorius, a friend and Ms Taylor were stopped by police for speeding, and the sportsman was angered when he was asked to remove bullets from the gun on his possession.

After he did so, it has been alleged by Ms Taylor that Pistorius fired a shot out of the sunroof after joking about shooting a "robot", which is a word used in South Africa to describe a traffic light.

Pistorius has denied that the incident, which is said to have taken place in September 2012, happened, but after being questioned by the defence, Ms Taylor maintained that it did occur.

It was also claimed in court that on one occasion Pistorius woke Ms Taylor up when they were in bed together after he heard something hit the bathroom window, which is the same bathroom where Steenkamp was shot.

Ms Taylor claimed that he left the room with his gun, but discovered that there were no signs of intrusion.

Pistorius denies all charges against him, maintaining that he mistook Steenkamp for a burglar when he fired the gunshots.