Leading defence lawyer, Robert Lithgow QC, defends the discharge without conviction ruling in the Losi Filipo case.

Victims of Losi Filipo's attack say they are "blown away" his discharge without conviction sentence can be appealed by police.

Karen Odell, the mother of assault victim Kelsey Odell, said she and Filipo's three other victims welcomed news of the appeal.

"We're just sort of blown away by it all.

Kai Schwoerer/ Getty Images Losi Filipo was discharged without conviction for a 2015 attack on four people.

"There's so many emotions going through at the moment."

READ MORE:

* Female victim of Losi Filipo speaks out on the attack

* Wellington Lions' pride hurt by Filipo attack - coach

* Leading lawyer defends judge's Filipo decision

* Why judge didn't convict Filipo for assault in the street

* Filipo groomed for a big rugby career from an early age

* NZ Rugby apologises to Filipo attack victims

* Kirwan apologises on behalf of NZ rugby community

The Solicitor-General reviewed the sentencing of Filipo by Judge Bruce Davidson and determined police may appeal on a point of law.

SUPPLIED Olivia Samuel was scared the attack would have a long term effect on her singing voice.

The Crown Law Office on Thursday afternoon confirmed police had filed an application seeking leave to appeal at the High Court in Wellington.

Filipo walked free after admitting to attacking four people in Wellington's CBD in October last year, after Judge Davidson felt a conviction could unfairly impact on his career prospects as a professional rugby player.

Karen Odell said New Zealand Rugby had offered support with legal costs and the next step would be to find out what would be involved with the legal process.

SUPPLIED Injuries suffered by Wellington man Greg Morgan after being assaulted by Wellington Lions rugby player Losi Filipo.

"There's a lot of mixed emotions since we're not sure what happens next," she said.

"It's huge.

"Until we know the process... trying to get 11 people [victims and family members] together to discuss everything is quite hard in itself. It's all phone calls at the moment."

Kevin Stent/Fairfax NZ Wellington Lions coach Earl Va'a apologises for the behaviour of Losi Filipo.

Filipo's lawyer Noel Sainsbury said he was unable to comment on his client's case now that it was before the courts again.

Neither the Wellington Rugby Union nor New Zealand Rugby were prepared to talk about the appeal, saying they did not comment on court proceedings.

Prime Minister John Key and Justice Minister Amy Adams have also refused to comment.

APPEAL NOT 'MOB' JUSTICE

A law expert insists the Solicitor-General's decision to let police appeal Filipo's sentence was not the result of mounting public pressure.

The discharge without conviction has fuelled wide public debate since it was revealed this week. Both the sentencing judge and New Zealand Rugby have copped heavy criticism for their part in it.

Auckland University law expert Dr Bill Hodge said the development was uncommon, but he was certain the backlash to the Filipo case would not have influenced Crown Law into taking the step.

"The Solicitor-General tries to make and, I think does a wonderful job, of seeing to it that the law is applied evenly.

"I would not like to think, myself, that if you get a public uproar, the Solicitor-General says 'Oh I better do something' just to satisfy the mob.

"That's not the function of the Solicitor-General and I think she's a very highly qualified and a person of integrity and I wouldn't want the perception to be dominant that 'all we need to do is make a fuss and we will get a challenge to a judicial decision'.

"That's not really what justice is about. It's not popularity. It's application of legal principles," Hodge said.

COURT BETTER THAN TRIAL BY INTERNET

There was a similar message from Robert Lithgow QC.

"This is the sensible process. There's people that say you can apply in both ways and people have got to decide whether it should be decided by courts or decided by a show of hands on the internet. I have spent 30 years believing that the courts are the better way to do it," Lithgow said.

"There is no more down-to-earth judge than Judge Davidson ... it's not for me to comment on how judges deal with these things. We just have to have a robust belief that the system will sort itself out," Lithgow added.

Both legal experts expected that it would take "some months" to get a decision on the case.

A BARRAGE OF CRITICISM

Filipo was initially retained as a contracted player with the Wellington Rugby Union, but after a day of intense public scrutiny following the release of the sentence, his agreement was terminated.

NZ Rugby came under fire after it was revealed neither they, nor the WRU, had contacted the four victims of the October 2015 attack.

After a barrage of media interviews on Wednesday morning, NZ Rugby chief executive Steve Tew said he would make a priority of contacting the victims.

Wellington Lions coach Earl Va'a made an apology to the victims on Thursday, as did former All Black Sir John Kirwan who made a public apology on Breakfast on behalf of the NZ rugby community.

In Va'a's apology he said the Mitre 10 Cup team was "deeply affected" by the actions of Filipo who was on the cusp of being selected as a wing.

'I MADE A HUGE MISTAKE'

Filipo himself said in a statement via the WRU he was remorseful for his actions and the effects they had.

"I understand why the victims of the assault do not want to talk to me and have not taken up an offer of restorative justice, but I would like to publicly apologise for my actions and the damage they caused," Filipo said on Tuesday.

"I made a huge mistake that my victims and myself will have to live with for the rest of our lives.

"I will continue to access the personal development and support structures I have engaged with over the past year. Though I cannot change what happened I recognise that I have been provided with a second chance and I want to continue use this opportunity to work hard."

Filipo was 17-years-old at the time of the assault. Victims said the rugby player had approached them angrily on a central Wellington street in the early hours. Two of the victims were men and two women.

Victim Olivia Samuel said it was "really scary".

"Losi was seeing red, it was like he was unrecognisable. He was so focused on fighting that he couldn't hear anything else going on around on him. It was really scary," she said.

"The whole fight kind of just ended, and I remember the two brothers running around the road screaming and cheering. It was like they were celebrating they had won. Meanwhile Greg was looking dead, they didn't care."

FIERCE LEGAL DEBATE ABOUT DECISION

Davidson's original decision to discharge without conviction has also caused fierce debate among those with significant experience in law.

Professor of Law at Auckland University Bill Hodge said on Wednesday it was wrong to go soft on Filipo.

"I find that unfortunate, it sets up a class system, it set ups a two standard, two tier system - one for athletes and one for everybody else," Hodge said.

But speaking to Radio New Zealand on Thursday Robert Lithgow QC said it was the legal system working as it should.

Lithgow criticised "wild and inaccurate attacks on the court system" and said the Sentencing act required – no matter how minor or serious – that a judge consider dealing with the matter without a conviction.

PROSECUTION APPEALS INCREASING

The Solicitor-General decides requests for appeals for prosecuting agencies such as police.

The figures show prosecuting agencies in New Zealand are asking for appeals more often.

Crown Law's own figures showed that in the 2013/14 year the Solicitor-General received 47 requests for prosecution appeals.

The following year that figure jumped to 96 requests.