The law and order select committee will continue to hear submissions in Auckland today on the Bail Amendment Bill, which proposes changes to bail laws to improve public safety.
"It was a horrific event for us and we will never recover," said Mrs Marceau, holding the box containing Christie's ashes.
"But her death was preventable. Christie and our pleas for safety were ignored. This resulted in an unimaginable nightmare. On November 7 my heart shattered. You cannot save my baby - but you can help the people of New Zealand."
Ms Mellor told the committee that Christie had expressed concerns for her safety if the accused was to be released on bail.
Several of Christie's friends also submitted that she had been "really worried" about what might happen if the man was granted bail.
Ms Mellor urged the MPs to make New Zealand safe and keep potential killers off the street.
"I know there is nothing that will bring Christie back to me, but because of the way the laws are, I had to walk down the aisle by myself without my sister in front of me," she said.
"Now I have to face every day without her. Do people know how difficult it is to cuddle an urn? I don't want anyone to have to feel the way I do."
Mr Borrell said he had "no doubt" Augustine would still be alive if Davis had been denied bail.
In a cruel twist, Davis was granted bail again after the murder. The Borrells had to hire their own lawyer to get the matter back before a judge and have him relocated.
"The justice system was taunting me ... I came so close to losing more than my son," Mr Borrell said.
"If you don't make the right decision now, sooner or later someone is going to take the law into their own hands. I can honestly say I almost did that myself.
"These changes are important. I have no doubt lives will be saved."
Mr Borrell said refusing bail more often would obviously cost money.
"I'm constantly hearing the argument that the country can't afford it. But we can't afford to do nothing. We can't afford not to morally."
The Marceau family teamed up with the Sensible Sentencing Trust to launch Christie's Law after she died.
The campaign aims to strengthen bail laws and get any legislative change made in Christie's name and a petition in favour of it drew more than 60,000 supporting signatures.
Other campaign supporters also made submissions yesterday and pushed for a regular review system for District Court judges to ensure they were performing adequately and for more weight to be given in court to police opinion on alleged offenders when considering bail.
