Judge John Brandts-Giesen told the offender "many people who would have done exactly what you did, even though it may be against the law".

A man who assaulted his wife, daughter and best friend after finding a love text has been convicted after all.

The 58-year-old Queenstown man, who has name suppression, was originally discharged without conviction after admitting the assaults in the Queenstown District Court in December.

Judge John Brandts-Giesen described the offending as "a nasty assault" but said it "had to be seen in its context".

123RF Judge John Brandts-Giesen's comments to the man, who attacked his friend and wife after discovering a love text between them, were "quite wrong", says appeal judge.

He said the defendant "saw red" when he discovered his friend and his wife had been having an affair.

"There would be many people who would have done exactly what you did, even though it may be against the law to do so."

The Crown appealed. Prosecutor Mary-Jane Thomas submitted the judge erred in granting the discharge without conviction, in particular his assessing of the gravity of the offending, the consequences of conviction and in his carrying out of the balancing test.

An appeal judge has now convicted the man, calling Judge Brandts-Giesen's comments "quite wrong".

On September 14 2017, the defendant was socialising at a bar in Queenstown with his wife, his two daughters and his best friend when he saw text messages between his friend and his wife, declaring their love for each other.

He told the court he was shocked and, in response, left the bar and walked down the street. A short while later, the man found the group near a cafe.

He went up to his friend, pushed him against a pole and held him there with his arm around his neck. A struggle ensued and both men ended up on the ground. The pair were separated by one of the man's daughters.

He then grabbed his daughter by the throat and pushed her to the ground, leaving bruising around her neck.

The two men then continued to push and shove each other. A group of people tried to pull them apart, including the defendant's daughter and wife. The defendant put up his boot and pushed at his wife, kicking her in the ribs. This caused her to fall backwards onto the ground and suffer minor injuries.

The defendant told police he was cross and wanted to "get" his friend. He said he could not remember grabbing his daughter by the throat or kicking his wife in the ribs.

In deciding whether to convict the defendant Judge Brandts-Giesen said the consequences of conviction were "out of all proportion" to what happened. He described the offending as "spontaneous and [of] and explosive nature".

He added the conviction would "put up certain barriers that should not have to annoy [the respondent] for the rest of [his] life."

In a decision released on Thursday, Justice David Gendall​ said assessing the gravity of the offending as moderate was "misguided".

He said Judge Brandts-Giesen appeared to be influenced in his decision by the views expressed by the defendant's wife in her victim impact statement where she said she did not want to him to get a conviction.

"I don't want to see anything bad happen to [him]."

Judge Brandts-Giesen's comments that anyone would have done the same as the defendant were "unfortunate". Judge Gendall said the comments tried to "normalise and minimise" the offending and blamed the victims.

"In my view, this is quite wrong, and it worked to significantly derail the judge's assessment of the gravity of the respondent's offending here."

He said Judge Brandts-Giesen erred in law by allowing the discharge without conviction.

He granted leave for the Crown appeal and set aside the decision to discharge without conviction.

He entered convictions against the defendant on each of the three charges and ordered the matter go back to the district court for sentencing.