Levesons plea for $1m rewards

Faye Leveson says the grief of losing her son Matthew was exacerbated by having to beg NSW Police to issue a reward for information into his disappearance.

Ms Leveson is now campaigning so other parents don't have to plead for a reward to be offered like she did after her son's 2007 disappearance.

"You're going through grief as it is, you're torn in half, your heart is being pulled out (and) you've got to beg for a reward to be put out there for information to come forward to find your son," Ms Leveson told reporters on Friday.

Matthew Leveson's remains were uncovered in the Royal National Park, south of Sydney, in late May after his boyfriend Michael Atkins told police where he buried the 20-year-old.

Atkins, who was acquitted of murder in 2009, led police to the burial site after striking two immunity deals with authorities.

He says he buried Mr Leveson in the park after finding him dead from a drug overdose in their bedroom following a night out.

NSW Opposition Leader Luke Foley said Labor would introduce legislation to parliament to increase all rewards for unsolved murders to $1 million.

Mr Foley, who was joined by Faye and Mark Leveson, asked for the government's support.

"If any good can come from the tragedy that fell the way of the Leveson family it's this, that we change the law, because the experience that Faye and Mark have had, no parent should ever have to go through," he said.

As it stands, a committee makes recommendations to the police minister about offering rewards for unsolved crimes on a case-by-case basis.

The minister has the final say but AAP understands the state government is reviewing the policy.

NSW is considering adopting the Victorian approach where rewards are based on the maximum penalty a court could hand down.

Homicides attract a $1 million reward, for instance.

A NSW Justice spokeswoman told AAP legislation wouldn't be required to change the state's rewards policy.

Rewards are usually offered to generate interest in an unsolved case and garner information.