Australia and Papua New Guinea to 'totally integrate' military in defence treaty, minister says

Australia and Papua New Guinea's military forces will become "totally integrated" as part of a landmark defence treaty between the two nations, the ABC can reveal.

The major security agreement is expected to be signed this week as Papua New Guinea marks 50 years of independence.

Australian Prime Minister Anthony Albanese, Defence Minister Richard Marles and Minister for the Pacific Pat Conroy are due to arrive in Papua New Guinea on Monday ahead of the celebrations.

PNG's Defence Minister Billy Joseph said the deal was a "mutual defence treaty" that would see the countries work together to defend each other's territories.

"We're not talking about interoperability, we're talking about totally integrated forces," he told the ABC.

"Australian Defence Force (ADF) and PNG Defence Force (PNGDF) both working together closely, using the same equipment … fighting together, defending our sovereignties as an integrated force."

Dr Joseph said the pact would contain an article similar to Article Four of NATO's founding treaty, which says member countries must consult when any of them feels their territorial integrity, political independence or security is threatened.

The deal will allow the ADF to recruit Papua New Guinea citizens and the PNGDF to recruit Australian citizens, a briefing document seen by the ABC said.

It is also understood that the treaty will provide a pathway for Papua New Guineans to gain Australian citizenship by serving in the ADF.

Speaking with the ABC's Insiders program on Sunday, Defence Minister Richard Marles said there was no question they would be paid the same as Australian recruits. 

"This is something we would be doing hand in glove with PNG as we walk down this path," he said.

"Numbers will clearly be managed and we need to be careful about how we do that if we're walking down this path.

"I'm very pleased to see the excitement that [PNG Defence Minister] Billy [Joseph] is bringing to this and it does, to be honest, reflect the way in which we've been going about this agreement since the moment we first met to do this refresh."

The neighbouring nations have, since June, been conducting formal negotiations over the defence treaty, which could have major implications for Australia's national security capabilities.

A submission is expected to be presented to PNG's cabinet for approval on Monday before it can be signed by both countries' prime ministers.

Dr Joseph said he expected unanimous support for the agreement within Papua New Guinea's parliament, which will need to ratify the agreement for it to take effect.

Defence pact a 'big strategic step' for Australia

The deal comes during a time of increasing geo-strategic competition in the region between China, Australia and the United States.

Dr Joseph said "external influences" had been working to undermine the Australia-PNG treaty, but he did not elaborate when pressed for details on the comment.

Michael Shoebridge, founder of the defence policy think tank Strategic Analysis Australia, said Canberra wanted to cement its place as the security partner of choice in the region.

"This is a pretty big step for PNG to say, 'Yes, we agree, you actually are our security partner of choice, and we mean it enough to put it into a treaty,'" he said.

"I think it says this is as close as you can get to an alliance relationship."

However, the deal was unlikely to curtail Beijing's growing economic influence in Papua New Guinea, Mr Shoebridge said.

"There is enormous political influence given to Beijing because of the growing economic dependence. And that's true for Australia, so I'm certain it will be true for PNG," he said.

In August, Australian Deputy Prime Minister Richard Marles travelled to PNG to open an upgraded naval base on Manus Island, signalling the new agreement would give both countries access to each other's defence bases.

"It's really clear … that we want to be able to operate out of each other's facilities," he told the ABC in August.

"When you look at what we're about to sign in the lead up to independence … you look at this base, you put that together, and this is a really big strategic step for our nation."

PNG may need help to match Australia's 'champagne tastes'

The deal between Australia and Papua New Guinea will send a message to the wider Pacific, Dr Joseph said.

"Other countries in our region look to us," he said.

"Even though we respect their sovereign decisions, we have chosen where and who we should put our trust in when it comes to security."

He said the agreement would not compromise the sovereignty of either country and could be amended in the future.

Since Papua New Guinea was proclaimed independent from Australia in 1975, the two countries have maintained close defence ties with joint training programs, military exercises and significant investments in infrastructure and equipment.

Mr Shoebridge said the integration would need to be managed carefully so that it would be "two sovereign nations and their militaries working together, rather than the PNGDF just becoming a sub-component of the ADF".

"PNG is about to celebrate 50 years of independence, and I doubt anyone in PNG wants to compromise that independence or be seen to compromise that independence," he said.

There may also be significant financial implications for Australia, Mr Shoebridge said, if the two militaries aspire to use similar equipment.

"[Australia's] defence force is not known as a set of bargain basement shoppers; they tend to buy the most expensive solutions for everything," he said.

"I can imagine there needing to be some further budget support for PNG to their military to allow them to have the champagne tastes that our military has."