Oscar Pistorius was involved in an argument at a nightclub at the weekend, his spokesperson has said.

The South African athlete had an altercation with businessman Jared Mortimer who said he was drunk, The Star newspaper says.

Oscar Pistorius’ spokesperson said the argument took place after Jared Mortimer started to “aggressively interrogate” him about his murder trial.

Reeva Steenkamp was killed at Oscar Pistorius’ home in South Africa’s capital, Pretoria, on February 14, 2013.

Jared Mortimer said he got involved in a row with Oscar Pistorius at the nightclub in Johannesburg’s upmarket suburb of Sandton, after the athlete insulted his friends and South African President Jacob Zuma’s family, The Star reports.

Oscar Pistorius had an altercation with businessman Jared Mortimer at a Johannesburg nightclub (photo AP)

“I took that personally because I am very good friends with a member of the Zuma family,” Jared Mortimer is quoted as saying.

Jared Mortimer said the Olympic sprinter was intoxicated and started to poke him in the chest while they were talking.

The businessman said he then pushed Oscar Pistorius away from him and the athlete fell over a chair.

The club’s bouncers helped Oscar Pistorius up, but were asked to remove him after he “had a confrontation with another man”, Jared Mortimer is quoted as saying.

Anneliese Burgess, a spokeswoman for Oscar Pistorius’ family, disputed Jared Mortimer’s version of events.

Oscar Pistorius, 27, was in the VIP section of the club when he was approached by a man who had since been identified as Jared Mortimer, she said.

“The individual, according to my client, started to aggressively interrogate him on matters relating to the trial,” said Anneliese Burgess.

She added that Oscar Pistorius “regrets the decision to go to a public space and thereby inviting unwelcome attention”.

On Sunday, hours after the incident, Oscar Pistorius tweeted for the first time since the death of Reeva Steenkamp.

He tweeted a Bible verse, a collage of pictures of his humanitarian work, and an extract from Viktor Frankl’s book Man’s Search for Meaning.

Oscar Pistorius’s murder trial was adjourned last week for closing arguments on August 7.