Australia and Papua New Guinea will promise to have each other’s backs under a new defence pact named after a dangerous reptile found in both countries – the crocodile.

But signing off on the deal may not be as snappy as Prime Minister Anthony Albanese hopes for because of a hold-up in gaining PNG Cabinet approval for the pact.

Albanese is in Port Moresby attending celebrations of the 50th anniversary of PNG’s independence from Australia and had hoped to finalise and sign the pact on Wednesday.

He said on Tuesday the PNG cabinet met late on Monday to give final approval but had no quorum because some ministers were back in their constituencies for independence celebrations.

But he expected his counterpart James Marape to sort it out quickly by ushering the process through his cabinet virtually.

The deal to closely integrate the two nations’ defence forces and set out mutual obligations if either nation is attacked, is called the Pukpuk Treaty, the ABC reports, a name derived from the pidgin word for crocodile.

When asked what Australia’s obligations under it would be, Albanese said the idea that PNG would be attacked and Australia would sit back and watch is “something that wouldn’t happen”, given the history and close ties.

Indonesia had been consulted on the pact and it had a good relationship with PNG, Albanese told Nine’s Today show.

The pact would take the PNG-Australia partnership to the next level, he told ABC TV on Tuesday.

“It will be a treaty similar to the relationship that we have with the United States,” he said.

“This will be seminal in our relationship with Papua New Guinea, our closest neighbour and one of our dearest friends.”

Marape has said he had “a moral obligation to build my military to a level that I can have the capacity to defend Papua New Guinea, every child”.

Australia’s Defence Minister Richard Marles and Minister for Pacific Island Affairs Pat Conroy will join Albanese for Wednesday’s meeting with Marape.

The landmark agreement will “integrate” forces either side of the Torres Strait, improve inter-operability and trigger mutual support in cases of conflict.

It will also enable PNG nationals to serve in Australia’s defence force with the same pay as other members and start a pathway to citizenship.

PNG Defence Minister Billy Joseph said on Monday the deal was a “mutual defence treaty” that would have the nations working together to defend each other’s territories.

Opposition Leader Sussan Ley said the treaty would bring “a transformation of our mutual partnership, providing the basis of deeper ties for the next 50 years”.

-AAP