The ABC reports the Australians were "likely tourists visiting a shooting range run by the Cambodian military for profit".

The broadcaster said the shooting range is well-known among tourists who pay to shoot AK-47 assault rifles and rocket-propelled grenades (RPGs) as well as throw hand grenades.

We did not invite them to train our soldiers but they just visited their friends.

General Chhum Socheat, Cambodian Defence Ministry spokesman

The shooting range, along with several others in the Phnom Penh area, are featured on internet websites showing images of Western tourists firing weapons.

Soldiers at the Kampong Speu base told the ABC they were ordered not to speak to media because allowing foreigners onto the range to fire weapons was illegal.

On Friday Cambodian Defence Ministry spokesman General Chhum Socheat clarified that the two Australians went to the base after being invited by Cambodian soldiers.

"We did not invite them to train our soldiers but they just visited their friends. But once they saw the mine, they picked it up and played with it before it exploded," AP reported him as saying.

Cambodian Prime Minister Hun Sen on Friday offered his condolences to Prime Minister Malcolm Turnbull over the Australian's death, during their bilateral meeting on the sidelines of an Association of South-East Asian Nations special leaders' summit in Sydney.

A spokesperson for Australia's Department of Foreign Affairs said the department was providing consular assistance to the families of the Australian man killed and the Australian injured.

"Due to privacy obligations we are unable to provide further information," they said.

Kampong Speu Provincial Hospital health department director O Van Then said the three injured people had received "light injuries" to their hands.

"The body of the Cambodian soldier has already been taken out by family while the Australian body is still at the hospital waiting to be taken by the Australian embassy," Vann Then said.

Around 60,000 Cambodians have been killed or wounded by mines since they were first deployed in large numbers in 1979, when the genocidal Khmer Rouge regime was ousted from power and began 18 years of guerrilla warfare.

AAP