FOREIGN Minister Julie Bishop says she has pushed the case for the return of Australians lost in the Korean War directly to her North Korean counterpart for the first time, opening a new window of hope for the families of the lost.

Ms Bishop said she spoke to North Korean Foreign Minister Ri Yong-ho on the sidelines of an ASEAN regional forum in Singapore and was confident he had taken Australia’s concerns about the return of war dead aboard.

“I noted the Americans had received the remains of some of their soldiers after the meeting between President Donald Trump and Kim Jong Un and I asked the Australians also be able to access the sites,” she said.

“We offered forensic and expert assistance so that we can recover those Australian remains of soldiers after the Korean War and he took that onboard.”

The renewed push to find the 43 Australian service personnel — including five West Australians — lost for more than 65 years began after Mr Trump met with North Korean leader Mr Kim in June.

North Korea has still not agreed to assist directly in the search for Australians lost during the conflict, but has begun returning the remains of some US service personnel.

Last month, US Secretary Mike Pompeo announced that North Korea had agreed to restart joint field searches of the Demilitarised Zone for the estimated 5300 Americans who failed to return home from the war.

North Korea also delivered 55 boxes of remains to US authorities recently, believed to be the bodies of American soldiers killed in the battle of Chosin Reservoir in 1950.

While Australia’s Defence Department said it had provided dental records, loss circumstances and DNA from families of Australian Korean War missing to be considered against any remains recovered by US authorities, it is still to sign a formal agreement with the US for testing of recovered remains.

Campaigners representing the families of Australians lost in the conflict said that agreement had been promised for at least three years but was still to be delivered.

They have also been pushing for testing of unidentified remains held by the US in Hawaii in the hope some lost Australians may have already been returned.

Mr Chester said US authorities had agreed to check the DNA of lost Australians against any remains recovered.

“In recent weeks, Prime Minister Malcolm Turnbull has raised the issue directly with US President Trump, and Foreign Minister Julie Bishop has raised it directly with United States Secretary of State Pompeo and Republic of Korea Foreign Minister Kang Kyung-wha,” he said.

Mr Chester said most of the Australian soldiers — including some West Aussies — still listed listed as missing in action were lost in the DMZ that separates North and South Korea.

“Defence has provided dental records, loss circumstances and DNA from families of Australian Korean War missing to be considered against any remains recovered by US authorities,” he said.

But Mr Chester played down the likelihood Australian families would hear good news in the short term.

“The challenges to recovery are immense. These include subsequent movement or deterioration of remains, development over potential recovery sites, land mines in the Demilitarised Zone and lack of access,” he said.

“Defence is prepared to respond should access to the Democratic Republic of Korea become possible for Australian authorities.”