Ex AFL star gives assault evidence

Former AFL footballer Nick Stevens says he would have given someone a "very serious injury" if he had kicked them 10 times, as alleged by his former girlfriend.

The former Carlton and Port Adelaide player has told Ringwood Magistrates Court his girlfriend threw glasses, punches and a phone at him and he denies ever kicking or bashing her.

She alleged he slammed her head into a bench and a wall before kicking her more than 10 times while she was on the ground on February 10, 2013.

Stevens said he had been an elite AFL kick, so if he kicked anyone 10 times they would have been seriously hurt.

"It wouldn't matter who it was ... I'd do someone a very serious injury," he told the court on Friday.

Stevens is contesting 30 charges of assaulting her while they were in a relationship and says he had never kicked his girlfriend.

He was shown photographs of bruises on her spine, neck, hips and buttocks and the scratch on her face after the alleged incident, but said the injuries were not there when they went to bed that night.

Stevens said the woman often bruised parts of her body carrying equipment at work.

He said the woman often punched him, threw glasses at him, and once smashed a mirror when she threw a phone at him.

Stevens said he had sometimes grabbed her arms when she charged at him to calm her down, and that might have left bruises.

He said the woman regularly accused him of cheating on her during their relationship, which ran from January 2012 to April 2013.

Stevens admitted in court to cheating on her in April 2013, but he originally told police he had never been unfaithful.

"I didn't want to get (the other woman) in trouble with her husband," Stevens said.

"In hindsight, I should have told the truth."

Stevens has pleaded not guilty to the assault charges, which stem from seven alleged incidents.

He said he had never punched, kicked or choked his girlfriend while they were together.

"It's all false. I deny the allegations. I've never done that," he said.

Stevens denied her allegation he had used cocaine and introduced her to it.

He said he had been drug tested at least five times a year throughout his 13-year AFL career without failing a test.

The case continues on Monday.