Australia and PNG already have deep defence ties but new foreign minister Justin Tkatchenko said in August he would like officials from the two countries to strike a formal treaty by the end of this year.

Mr Marles told journalists that both countries had a "very ambitious" agenda on defence cooperation, but he would like to formally elevate existing cooperation with a treaty level security agreement as quickly as possible.

"The defence relationship is one of the strengths of the bilateral relationship, but this is really playing to that strength," he told journalists after the meeting.

He said a treaty would seek to make defence cooperation "even closer … where we are having our defence personnel working alongside each other more, and in the process making both our defence forces more capable.

"And that's across all domains – maritime, aviation and army."

Mr Marles later said Australia also wanted to help PNG address any capability gaps in its armed forces.

"Aviation might be an area where we could do more," he said.

"Already we supply the bulk of the maritime capability for the PNG defence force, but we feel there are opportunities for us to do more."

He also flagged that he would like to pursue deeper defence cooperation across the Pacific, including by offering wider training opportunities to countries with defence forces, including Fiji, Papua New Guinea and Tonga.

When asked if he would like to sign treaty level agreements with additional Pacific nations which have armed forces, Mr Marles said he would like to see Australia's defence relationships "evolve" in the region.

"We are focused on PNG right now. We will continue to try and evolve our relationships with other countries in the Pacific as well," he said.

"All of this is part of doing the work, making sure we are present in the Pacific that we are focused on developing countries in the Pacific and establishing ourselves as the partner of choice for countries in the Pacific."

While anxiety about China has propelled Australia's renewed push to deepen defence ties in the Pacific, Mr Marles insisted that this is not the primary driver.

"We are obviously in a very challenging and complex strategic world and there's no doubt China forms part of that landscape," he said.

"But actually this is much more about the relationship between two countries – in the case of Australia and PNG – who don't just see each other as friends but really see each other as family."

"It's much more about building our relationship on its own terms."