WA Police are looking closely at Victoria's plan to offer $1 million rewards for all unsolved murders, with breakthroughs still needed in more than 40 WA homicide cases dating back 40 years.

Victims' families have thrown their support behind the idea, which they believe could generate much needed new information about the deaths of their loved ones and help bring their killers to justice.

The Victorian Government said last month it would offer $1 million and a full pardon to anyone with information that helped to solve an old case - as long as the person making the claim was not directly involved in the death.

Supt Anthony Lee, who heads WA's major crime squad, said the Victorian model was "worthy of consideration" and talks had been held with his Eastern State's counterparts about its merits.

But the final decision rested with the State Government which declined to comment yesterday.

Grieving parents Pat and Ian Govan said $1 million would be money well spent if it helped them recover the body of their daughter Lisa who police suspect was murdered in Kalgoorlie-Boulder 15 years ago.

The reward on offer for information that helps to convict her killer is $50,000.

"I believe $1 million is a life-changing amount of money and it may just be what is needed to finally get someone talking after all this time," Mr Govan said.

Of the more than 40 unsolved murders or suspected murders listed in _The Weekend West _today, rewards have been offered only in just a handful of those cases.

The suspected murder of Perth woman Sarah McMahon in 2000 was overlooked despite pleas from her family. Sarah's sister Kate McMahon said a big reward was the only hope her family had of ever getting the answers they so desperately need.

"My parents and my family have been put through absolute hell for the last 14 years and it would mean the world to us to finally have some closure and to know the person who has done it did not get away with it," Ms McMahon said

Shadow police minister Michelle Roberts said she could see no valid reason for the Government not to follow Victoria's lead.

"These cases remain open forever and given what police must spend on conducting cold case reviews every few years . . . I think there is nothing to lose and everything to gain," she said

One of the reasons Victoria agreed to change its reward system was concerns among families about differences in the amounts that had been offered which varied from $20,000 up to $1 million.

In WA, the reward posted for the Claremont serial killings is $250,000. The same amount has been offered for information about teenager Hayley Dodd's suspected murder in 1999.

But the reward for one of WA's most baffling mysteries - the 1975 execution of brothel madam Shirley Finn - is just $20,000. The same amount was offered after the disappearance in 1980 of Lisa Mott and in both cases the figure has not increased.

The family of missing Kalgoorlie-Boulder man Charlie Park will mark the third anniversary of his suspected murder today.

"The sort of people I believe you are dealing with in dad's case would sell their own grandmothers for a million bucks, so I think it is high time a reward was offered," Mr Park's daughter Nola Gregory said.