The woman who called police testified in court that she was having an affair with one of the two senior constables called to her house on August 5, the discovery of which led her partner to push her and grab her keys and phone.

That on-duty, uniformed officer also took her to his house after she called for help, the woman told the court, rather than the police station as she requested.

The testimony was made during her partner's common assault hearing in Cooma Local Court in December, during which she recanted earlier complaints that he tried to break her arm and bruised both forearms.

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The common assault charge and apprehended violence order against the partner was dismissed due to her changed evidence.

The woman told the court she had previously had an affair with one of the attending officers, and called his number rather than triple-zero after her partner of six years found out and argued with her about it.

The officer and another senior constable attended the scene, court documents said, and picked the woman up outside her neighbour's house after she called at about 10.30pm on August 5.

But the woman did not arrive at the police station and provide a domestic violence evidence in chief interview until the afternoon of the next day.

She told the court one of the officers told her they were going to his house because "you need to go somewhere safe for the night".

"I wanted to go to the police station," she said.

"[The senior constable] said you can't go to the police station, I'll just take you to mine and then I can take you to the police station in the morning."

The woman told the court she stayed in the officer's spare room overnight, then went to the police station with him the next day through the back entrance.

The officer in charge of the domestic violence case, Daniel Draper, told the court via telephone that he was first aware of the matter when the woman arrived at the police station.

He told the court an event number was created from the night the woman was picked up, but there was no record that she told the attending officers she had been assaulted at the time.

The court heard the attending officers did not interview the defendant when they first picked up the woman down the street.

Neither officer was present, nor called to give evidence at the hearing about the night's events, which Magistrate Michael Antrum described as "curious".

"It is highly irregular that an attending officer would then take the complainant home," he said.

"Indeed, the attending officer was one of the reasons for the dispute in the first place on the evidence today. Any pretence of objectivity or professional distance is entirely absent in this matter."

Prosecutor Sergeant Danielle Byrne said she was aware the woman planned to change her version of events in court, but "wasn't aware of the extent" to which it would be altered.

Defence solicitor Garry Huggett submitted that the defence had no case to answer, based on the prosecution's evidence.

Mr Antrum dismissed the charge and an attached apprehended violence order because of the woman's rejection of her earlier evidence indicating an assault.

He said he hoped the conduct of the two attending officers was under review.

"In the absence of those officers to rebut what has been put by the complainant in these proceedings there is some very, very concerning conduct by these officers," he said.

"While it is not for the court to determine matters of professional standard or rigor I would hope that it is a matter that is being reviewed by the commissioner."

A NSW Police spokeswoman confirmed an investigation was underway, but said "it would be inappropriate to comment further".