The lawyer for a Western Australian man wrongly convicted of murder 50 years ago says his client is surprised by the amount of compensation awarded to him.

Darryl Beamish was today awarded $420,000 by the State Government.

Mr Beamish, who is deaf and unable to speak, was convicted of murdering socialite Jillian Brewer in 1959 and spent 15 years in prison for the crime.

This was despite a later confession to the murder by Perth serial killer Eric Edgar Cook.

In 2005, the Court of Appeal quashed Mr Beamish's conviction on the basis that a substantial miscarriage of justice had occurred.

Michael Dawson says Mr Beamish had requested $500,000 to help him live a comfortable life in retirement.

"He's a little bit surprised I suppose when we asked for a relatively modest amount, that the government decided to give him slightly less than we did ask for," he said.

Mr Dawson says the payment will help give his client financial security.

"He was only ever after a relatively modest sum anyway, just to simply give him that little bit of security into his old age," he said.

In a statement, WA Attorney-General Christian Porter said ex-gratia payments were not intended to fully compensate individuals for loss or detriment suffered.

"In this instance, the Government is satisfied that sufficiently extraordinary circumstances exist to justify an ex-gratia payment," he said.

"This payment is intended to express the state's sincerest regret for what occurred and provide him with a measure of comfort and financial security in his retirement."

Is it enough?

The compensation payment follows other high-profile, wrongful imprisonment payments to West Australians Andrew Mallard and John Button.

Mr Mallard was convicted in 1995 of the brutal murder of West Australian woman Pamela Lawrence and sentenced to 20 years in jail.

He served 12 years until the combined efforts of a journalist, politician and a team of high-profile, pro bono lawyers finally saw him exonerated.

Perth man Mr Button was convicted for manslaughter for the 1963 hit-and-run killing of his 17-year-old girlfriend Rosemary Anderson.

He served five years in prison and the conviction was overturned in 2002.

The WA Government awarded him $460,000 in compensation.

Mr Button, who also had a lengthy battle to clear his name, has questioned why the payment is so much lower than the amount awarded to Mr Mallard.

"I find it pretty hard to understand why $420,000 for him and a similar amount for myself and yet over two million for Andrew Mallard," he said.

"I believe Andrew was worth more than that - I believe we all are - but why the difference?"