Key Points:

Sitiveni Sivivatu's mother says the domestic dispute between her son and his wife which led to the All Black being charged with assault was "a clash of cultures".

As the Fijian-born winger played for his Super 14 side the Chiefs against the Western Force in Hamilton yesterday, Koleta Sivivatu was celebrating her birthday in Suva.

She told the Fiji Times that her son rang her on Friday night and again on Saturday morning to wish her a happy birthday.

Koleta told the reporter she did not condone Sitiveni's actions in slapping his wife Suliana.

"I don't think it's acceptable but it was a personal matter," she said. "I think it was a clash of cultures.

"His wife was brought up in a Tongan family where the women are the more dominant in the house, while for Siti it is the man. I do think it has been blown out of proportion because it was a personal matter."

Meanwhile a family friend of the couple told the Herald on Sunday that Sitiveni and Suliana had reconciled completely, and that the relationship had returned to the wedded bliss it was when they married last January.

"It was just a domestic, which got out of hand unfortunately," the friend said. "They're still in love and respect each other."

In the Hamilton District Court on Thursday, Judge Phillip Connell discharged Sivivatu without conviction over the assault on his wife but lifted name suppression, leaving the All Black to face the full glare of the national media. Sivivatu had admitted the March attack.

His manager Laurie Flitten said he wanted to move on.

"He's made a mistake and regrets the decision, both of them do, they are very private people.

"It should never have happened and unfortunately it's been blown out of proportion."

Flitten believed the story had not been handled well by the media. "There's a hell of a lot more serious crimes going on, I'm a little disappointed in how it's been reported.

"There are a lot more incidents which are life-threatening which do not see the front pages. It's time to move on. We just want to let it die."

Koleta Sivivatu also said her son was remorseful.

"He's sorry for what he did. He said he snapped out of frustration after a personal argument. He said he had just come back from training and they had an argument. He said he gave her a slap on her face. She then reported the matter to the police."

The school teacher described her son as "very disciplined and humble" and said he had never done anything like this before.

"He's not a violent person."

A Waikato rugby source said the court hearing had weighed on Sivivatu's mind and affected his form in recent weeks.

"Of course it has. How much? Only Siti knows because he keeps it to himself. He handles it his way."

Sivivatu's wife, Suliana Mone, was dux of Queen Salote College in her home country of Tonga in 1999. A law student, she was studying at Auckland University but transferred to Waikato to be with her husband. She tried to withdraw the charges against him.

Former All Black coach John Hart said he was saddened by the publicity surrounding the case as it appeared to him to be "totally different to that which Joe Average would receive". However, he said the police were probably "between a rock and a hard place" when it came to prosecuting Sivivatu, because if they had used their discretion and not taken it further they may have been criticised for being overly lenient on an All Black.

"It seems wrong to me that someone involved could ask for the case to be withdrawn, yet it has to proceed," he said. "I know it is the law but it is disappointing and it does seem to be a mark against people who have some standing in society, unfortunately."

Asked what he thought of Sivivatu's discharge without conviction and whether, as a former All Black coach, he would select a player who had been in such trouble, Hart said: "It is not a matter for the coach. This is not a playing issue and not a coaching issue. It is an administrative issue and it comes down to the individual, his employer and the terms of his contract."

The New Zealand Rugby Union has begun an internal investigation into the matter, under the terms of the players' collective agreement. In a statement, deputy chief executive Steve Tew said: "Any player misconduct is a serious concern and now the legal process is complete for Sitiveni we, as the NZRU in conjunction with the Chiefs, have started our own misconduct process.

"The collective agreement requires the details of individual cases are confidential, but I can say that the union has, where appropriate, handed down fines and suspensions in the past."

A Waikato rugby union source told the Herald on Sunday that the union was "very hot on it. There's a hearing to take place but they don't know what's going to happen. It's pretty daunting for him [Sivivatu]. It's not a pleasant time."

Asked if he thought Sivivatu was being punished twice by having the court appearance and lifting of name suppression, plus facing an NZRU inquiry, Hart said there was no other option than to have an inquiry and that the NZRU was also in a difficult situation.

"You can't live outside the terms of employment that are listed in your contract. There will be parts of that contract which cover bringing the game into disrepute and the NZRU have to act on that. The way you behave outside the game is an issue - that's the way it is."

Sivivatu played at fullback in the Chiefs' 64-36 win over the Western Force in Hamilton yesterday, but played little part in the high-scoring day game.

At the after-match press conference, Chiefs' coach Ian Foster told reporters that Sivivatu's off-field personal troubles had not affected his on-field performance.

"I thought he did really well," said Foster. Asked if he had considered not playing Sivivatu because of the wing's difficult week, Foster replied "no".