When Ray Whitby and a handful of Australian Navy colleagues stepped onto an island off the WA coast after Britain had just wrapped-up its nuclear weapons testing, they had no idea their lives would be changed forever.

"We were in shorts, sandals and short-sleeved shirts," Mr Whitby said.

A scientist who was with them that day on the Montebello Islands off the Pilbara coast — and who was decked-out in full protective clothing — delivered a grim message.

"He told us 'you guys shouldn't be here, this is deadly'," Mr Whitby said.

Later investigations found the weapons tested on those islands — believed to be around four times more powerful than those dropped on Hiroshima and Nagasaki in World War II — had left behind a level of radiation that was "definitely unacceptable to personnel".

When Mr Whitby and his colleagues returned to their ship they attempted to decontaminate themselves, but were later told the water they used to do this, also contained high radiation levels.

So too, did the kitchen items they were using to prepare meals.

The group is fighting for health benefits for ex-servicemen exposed to radiation in the Montebello Islands. ( ABC News: Jacob Kagi )

'There's no excuse whatsoever'

Mr Whitby said the effect was devastating, with many of his fellow servicemen on that HMAS Fremantle mission dying as early as their 30s, or suffering lasting health issues.

He has fought cancer and saw his wife miscarry five times.

"We were used as live guinea pigs," Mr Whitby said.

"There's no excuse whatsoever, we all joined the service to help our country and do our part."

The Ex-Services Atomic Survivors Association says giving a gold card to the veterans would cost the government very little. ( Supplied )

Many in similar circumstances to Mr Whitby had a big win last year, when the Federal Government announced a $133 million program to give nuclear veterans access to the gold card, which provides veterans with lifelong no-gap medical insurance.

But this would only apply to veterans exposed to radiation between October 3, 1952 and June 19, 1958.

Mr Whitby and his colleagues were exposed 85 days after the cut-off date.

One of those colleagues, ex-serviceman Jim Marlow, describes the situation as infuriating.

"Why it differentiates between one and the other I have no idea," he said.

"We are not recognised, we simply get ignored."

Montebello Islands nuclear testing survivor Jim Marlow says the situation is infuriating. ( ABC News: Jacob Kagi )

A small cost for a big benefit: veterans

Mr Marlow, Mr Whitby and others have spent years campaigning for access to the gold card, believing it to be a fair request given the challenges they have faced in their later lives.

"I paid hundreds of thousands of dollars out over the years on cancers and various medical situations that I had," Mr Whitby said.

"It has been dreadful."

The exact number of people in the same situation is unknown, but the Australian Ex-Services Atomic Survivors Association believes it to be relatively small and one that would not require a big financial outlay from the Federal Government.

Veterans affairs benefits are a federal issue, but the State Government has vowed to lobby the Commonwealth to extend medical benefits to Mr Whitby and others in the same circumstance.

Mr Whitby's son, Reece, is a first-term Labor MP in WA and used his platform in State Parliament to urge the Commonwealth to act.

"If we can't treat veterans from the 50s fairly, how can current members of our armed services have confidence they will be treated fairly in years to come?" Reece Whitby said.

A spokeswoman for Federal Veterans Affairs Minister Darren Chester said the eligibility dates were determined on the basis of scientific evidence.