A Kiwi sports star has been granted a discharge without conviction and won permanent name suppression after an assault on his estranged partner which left her huddled in a ball to protect herself.

The sport he plays cannot be revealed without breaching the Judge's suppression orders.

But he has had a long and ongoing domestic and international career representing New Zealand at the highest level.

The possibility a conviction could jeopardise his current and future sporting contracts and international travel was cited by Judge Simon Maude at the man's sentencing in an Auckland court on Monday afternoon.

Judge Maude also said publication of the man's name was likely to cause extreme hardship.

"I regard publicity, with the ferocity that social media can bring, as likely to cause [the defendant] extreme hardship," Judge Maude said.

The man pleaded guilty to common assault and wilful damage seven months after the fact.

Details of his offending were summarised by Judge Maude at the hearing.

Early on November 28, 2020, he arrived unannounced at the victim's home.

The two were separated after a years-long relationship but were having counselling with a view to reconciliation, Judge Maude said.

On arrival at the victim's home, the man was let in by an associate of the victim.

He confronted the woman, calling her a w**** and a s***.

The man then grabbed her engagement ring and tried unsuccessfully to remove it from her.

"She had rolled into a ball," Judge Maude said.

The man then took the keys to a vehicle that belonged to him but which he had given the victim permission to use.

The victim followed him outside whereupon he smashed her phone on the footpath.

She was left with bruising to her arms. The woman would go on to file an affidavit in support of name suppression.

She was also supportive of discharge without conviction.

Police senior prosecutor Sergeant James Gallagher opposed both the application for permanent name suppression and for discharge without conviction.

"Simply being well known should not be an automatic bar to prosecution," he said.

Other aspects of Gallagher's arguments cannot be reported without breaching the judge's suppression order.

The man's lawyer, Hannah Stuart, said his chosen sport was "his life" and "all he's done".

Stuart said the man risked being "blackballed" in his sport if he was named and convicted.

"As a public figure, he also runs the risk of online bullying."

Stuart said a conviction could jeopardise future overseas travel and therefore his ability to earn money as a professional.

"The gravity of the offending really has to fall at the lowest end," she said.

Stuart said the man had made donations to Women's Refuge and compensated the victim for her phone.

The assault charge he admitted has a maximum penalty of six months in prison or a $4000 fine, while the intentional damage charge carries the possibility of three months or $2000.

Judge Maude said in order to be discharged without conviction he had to be satisfied the consequences of the conviction had to outweigh the gravity of the offending.

"I rate the gravity as low towards the upper end of low, taking into account the persistence of the incident," Judge Maude said.

Judge Maude said international travel was an essential element of the man's career as a professional athlete.

"I accept that given [the man's] particular career the consequences of conviction are out of all proportion to the gravity of his offending."

He granted the man a discharge without conviction and permanent name suppression.

"I do not believe that suppression is contrary to public interest which it would be if the violence was of a more serious nature."