Kay Waldron was 11 in January 1951 when her family received word her older brother, Royal Australian Air Force pilot Geoff Stephens, was missing in action in the Korean War.

The 23-year-old flew with the RAAF's famed No. 77 Squadron; his plane is believed to have been shot down over North Korea.

"My mother took to the bed for 12 months — she was in depression," says Ms Waldron, now in her 70s.

"She was really never the same again. All of us weren't."

Pilot Officer Stephens is one of 43 Australian servicemen still unaccounted for more than six decades after fighting ended on the Korean Peninsula in 1953.

Officially listed as missing in action, the men are presumed dead, but their remains have never been repatriated.

The search for answers

"I just want closure — all the families feel the same way," says Ian Saunders OAM.

His father, Private John Philip Saunders, was one day shy of 26 when he was reported missing on the Korean Peninsula in January 1953.

Private John Philip Saunders (centre) was reported missing in action on the Korean Peninsula in January 1953. ( Supplied: Ian Saunders )

Now 73, Mr Saunders has used official Canberra war diaries and declassified Australian and US military documents to try to piece together what happened to his father and other missing servicemen.

He has become a leading voice in the families' campaign to repatriate remains, and is unhappy with the pace of Australia's investigation into its missing.

"It's taken too long," Mr Saunders says.

"[Australia has] recovered and identified remains, if we can, in all the wars that Australians have served in since the Boer War.

"So, why hasn't the government done anything about it is a very good question."

Bruce Gillan is searching for answers about the fate of an uncle who he suspects may have survived the Korean War and been taken to a prison camp in the Soviet Union or China.

The solicitor's namesake, RAAF pilot Bruce Thomson Gillan, disappeared in January 1952 at the age of 21.

Bruce Thomson Gillan is another pilot who disappeared during a mission over North Korea. ( Supplied: Bruce Gillian )

"The [Australian] records of Bruce's service that I have been able to obtain have one interesting notation which says: 'In 1952 believed to be prisoner of war'," Mr Gillan says.

"That information was never passed on to my parents."

Mr Gillan says he has seen declassified US intelligence documents that appear to show the American military believed his uncle may have been taken captive.

"There must be more information that can be released and it should be released — not just for [my uncle] but all the families," he says.

Investigating Australia's missing

Australia and the Korean War From 1950-53, Australia fought as part of a multinational force defending South Korea from an invasion by Communist forces of the North.

From 1950-53, Australia fought as part of a multinational force defending South Korea from an invasion by Communist forces of the North. Australia deployed more than 17,000 servicemen — Army, Navy and Air Force — in the Korean War.

Australia deployed more than 17,000 servicemen — Army, Navy and Air Force — in the Korean War. About 340 Australian service personnel were killed and more than 1,000 were wounded.

About 340 Australian service personnel were killed and more than 1,000 were wounded. An Armistice in 1953 left North and South Korea formally at war to this day.

An Armistice in 1953 left North and South Korea formally at war to this day. The Korean War was one of Australia's largest overseas military deployments since WWII.

The Korean War was one of Australia's largest overseas military deployments since WWII. It marked the last time the Australian government called for volunteers for overseas combat.

The Australian Defence Force believes most of Australia's missing servicemen were last known to be alive in North Korean territory, including what is now the Demilitarised Zone which separates the two Koreas.

According to the Department of Defence, official efforts to find, recover and identify the missing men began "from the time of initial loss".

The department says that since the 1953 Armistice, Australia has enquired about its wartime missing through United Nations Command, the US-led international force under which Australian troops fought on the Korean Peninsula, and US authorities.

In a statement the Department of Defence Army Headquarters says Defence and other Federal Government agencies, "raised the matter intermittently at least back to the 1990s when full provision of Australian loss of information was exchanged with US authorities".

At last year's Singapore summit between presidents Donald Trump and Kim Jong-Un, North Korea agreed to transfer thousands more remains to the US.

After the summit, then-foreign minister Julie Bishop revealed Australia had offered "expert and forensic" assistance to North Korea to begin its own official investigations into its Korean War missing.

"Key to access [to North Korea] is what is happening at the geopolitical level," says Andrew Bernie.

Mr Bernie is the manager of the Army's Unrecovered War Casualties Unit, which oversees the investigation and recovery of all missing Australian military personnel from former warzones.

If North Korea granted Australia access to sites of interest, he says, an Australian expert investigative team could be ready for deployment within two weeks.

The Korean War is sometimes called the "forgotten war", but Mr Bernie says that is "absolutely not" the case.

He says his unit is prioritising the Korean War missing over investigations into more than 25,000 Australian servicemen missing from other conflicts.

"The Korean War is absolutely not a forgotten war and the families [of the missing men] are not forgotten," Mr Bernie says.

A federal working group, which includes relatives of the missing servicemen, has for several years focused on a memorandum of understanding (MOU) with the US to formalise co-operation on identifying remains sent there from the Korean Peninsula.

The MOU was signed in August 2018.

A separate MOU is being developed with South Korea, where more suspected Korean War remains were reportedly uncovered this year.

What would it take to bring the remains home?

Relatives of Korean War veterans, including Ian Saunders (centre), gathered in Seoul late last year. ( Supplied: South Korean Ministry for Patriots and Veterans Affairs )

In 2008, then-US State Department official Frank Jannuzi was called to revive cancelled US diplomatic talks with North Korea, including on repatriating wartime remains.

He says any repatriation negotiations with North Korea should be treated "purely as a humanitarian issue".

"[The matter] should be as divorced from politics as possible and have nothing to do with sanctions," he says.

"The [Australian] Government will have to find a way that ensures this kind of humanitarian operation is compliant with relevant United Nations sanctions [against North Korea]."

Sorry, this audio has expired What will it take to repatriate the remains?

Clive Williams, a former director of security intelligence for the ADF, believes Australia has little chance of making progress without a diplomatic gesture.

The Pyongyang Government closed its embassy in Canberra a decade ago, and Mr Williams believes restoring the country's diplomatic representation to Australia could be key.

"It would be quite a big breakthrough for North Korea to be able to re-establish a diplomatic facility in Canberra," he says.

"It would open the door for us to be able to pursue MIA recoveries.

"If we don't do that, there's less chance of us being successful."