On June 19 Matthew Hunt was meant to have dinner with his mother Diane after work.

But he never made it.

Several hours after he put on his beloved blue uniform, Constable Matthew Hunt was dead - gunned down in an Auckland street while attending a routine traffic stop.

Today (Wednesday) his mother will present a petition to Parliament in his name and honour, calling for changes to the Sentencing Act 2002 and the Parole Act 2002 that would see anyone convicted of murdering a police officer receive a mandatory life sentence and have their parole eligibility automatically declined.

It's been an "overwhelming" four months for Diane Hunt since that devastating day, but she is determined to do whatever she can to ensure no other frontline officer is killed and no other mother has to bury their son or daughter in similar circumstances.

"Matthew was 28 years old and he did not deserve what happened to him - he was meant to come home, he deserved a life," she told the Herald.

"He was totally robbed of that, all because he put on a New Zealand police uniform and there is an element of society who have no respect for that uniform.

"He gave his life for his country, on a suburban street in Massey, trying to do the right thing.

"I want there to be a legacy and I will devote the rest of my life to that - Matthew deserves that."

Hunt was killed as he and his partner tried to pull over a car just before 10am on June 19, a Friday.

He was shot multiple times with a long-barrelled gun, which the Herald understands was a high-powered assault rifle.

Hunt's colleague was also shot several times but managed to get away and survived the attack.

A man has been charged with murdering Hunt, attempting to murder the other police officer and wounding a member of the public as he allegedly fled the scene in a car.

A woman has been charged with being an accessory to Hunt's murder after the fact, by enabling the accused killer to leave the scene in a car and avoid arrest.

Both have pleaded not guilty and are in custody awaiting trial in the High Court at Auckland next year.

The scene of Constable Matthew Hunt's alleged murder. Photo / NZ Herald

Diane Hunt launched a petition on July 30 - the day her son would have turned 29.

"I want no parole for the killers of police officers in New Zealand - a murder sentence here can mean about 10 years in jail and I don't believe that's an appropriate sentence for the murder of a public servant doing their job," she said.

"First responders have this on their shoulders every day they go to work, they all need to get home.

"I'm don't want to suggest arming the police, but there needs to be another deterrent and this could be the way to stop this happening to any other person in New Zealand."

More than 39,000 people have signed the petition, which will be presented at Parliament this morning.

Diane Hunt said she was "extremely nervous", but proud that her son had had such a big impact and that so many people were supporting her.

"I don't want anyone else to go through this," she said, her voice cracking and tears flowing at the memory of her slain son.

"I don't want anyone to lose their life as Matthew has, for their uniform."

Diane Hunt said she and daughter Eleanor had struggled since the alleged murder.

"It's been awful - we were a family of three and now Matthew is gone… it's just awful, there are no other words, you can't really say anything else," she said.

"Some days I don't actually believe it happened… my daughter lives in India and she has been here a long time, she needs to get back and start her life again as she was before June 19.

"I just sort of muddle my way through, you never know what the next day will bring."

Diane Hunt said she had one goal in life since her son passed - one purpose.

"I want to make Matthew proud," she said.

"He was such a good person, who only wanted to help others and he had the potential to help a lot of people throughout his life.

"He had a lot to offer and he was just at that cusp of becoming a man - I will never get to see that adult version of Matthew, I was robbed of that, and he was robbed of it too."

It was Hunt's lifelong dream to become a police officer and he'd been on the front line for two-and-a-half years when he was killed.

He was working hard to pass exams to get into the Criminal Investigations Branch and become a detective.

He was passionate about policing, helping, people.

"I really believed that he was supported, safe," said Diane Hunt.

"I honestly didn't fear or worry for him - stupidly.

"Our police are unarmed and they are expected to confront armed offenders unarmed and it's absurd really ... I had no idea what the police were up against until Matthew's death."

Diane Hunt is calling on lawmakers to be brave and bold and protect the front line.

In Victoria, Australia the law was changed in 2016 to ban parole for police murderers.

In New South Wales cop killers are sentenced to imprisonment for "the term of the person's natural life".

Diane Hunt wants the New Zealand Government to do the same.

"I am trying to do the right thing, I don't know what else to do - I am not going to Matthew's death just be the end of it and just accept that it's what happened to him.

"I will remember Matthew for his decency and for the wonderful person he was.

"There are 14,000 police officers in New Zealand with families - these people are there to serve and protect their community which is what Matthew wanted to do, to help.

"They all deserve to come home and there needs to be more deterrence to stop people from thinking they can shoot them as they see fit.

"There needs to be more protection - a life sentence for taking a life."

Diane Hunt will present the petition to Police Minister Poto Williams and her local Orewa MP Mark Mitchell at 11am.

Text By: Anna Leask, NZ Herald