Sergeant David Berry appeared in the Ballarat Magistrates Court on Tuesday for the contested hearing, charged with one count of unlawful assault against Ballarat woman Samantha Mitchell in the early hours of May 4, 2017.

Berry told the court he did not "think she was injured" to the extent she was - with her nose broken in two places and a bruised and swollen face - but denied he had left the scene immediately, only to call police, out of malice.

"I was trying to work out what's happened and why she was trespassing ... I didn't know how hard I hit her."

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In his closing remarks, defence barrister Malcolm Thomas said his client was "unshaken" under cross examination as he was being truthful about punching the complainant in self-defence.

"He hits out in a moment while concerned he's going to be hit, having had the experience of being hit without warning before," Mr Thomas said.

Prosecution barrister Matthew Cookson said Ms Mitchell did not "bear the characteristics of exaggeration" in her testimony.

Mr Cookson said Berry had not called an ambulance or asked if the crying woman was okay after she fell to the ground, which spoke of the "state of mind mere seconds" before the blow was landed.

"To slug her across the face just goes so much further than a reasonable person would have done in the circumstance," he said.

Magistrate Frank Jones will make a judgement on June 7.

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