Australia and Papua New Guinea have committed to a new security deal which is set to be signed in June.
Leaders Anthony Albanese and James Marape agreed to a joint statement of commitment to a security treaty between the two countries at a meeting in Port Moresby on Thursday.
In the joint statement, the respective prime ministers said the deal would "reflect the evolving nature of our shared security interests, recognising that non-traditional security challenges, such as climate change, cyber security, and economic elements of statecraft, affect our strategic environment".
Foreign ministers have been asked to conclude negotiations by the end of April so the leaders can sign it in June.
Earlier in the day, Mr Albanese became the first foreign leader to address PNG's parliament, pledging the new defence pact with Australia's northern neighbour.
"Australia and Papua New Guinea have a chance to deepen our defence ties by enhancing our national security co-operation and achieving a swift conclusion to negotiations on a bilateral security treaty," he said.
"A treaty that will underpin our work together to address PNG's priority needs including law and order challenges, strengthening the justice system and rule of law and a treaty that builds on the family-first approach to regional security."
Australia, the United States and other allies have been seeking a deal after China signed a security pact with the Solomon Islands.
"This can be a decisive decade for peace, prosperity, unity and security in the Indo-Pacific," Mr Albanese said.
Mr Albanese received a ceremonial welcome as he touched down in Port Moresby, becoming the first Australian leader to visit the country since 2018.
He later gave Mr Marape an Akubra Cattleman hat made in Kempsey during talks.
"We are elevating to higher heights how we relate," Mr Marape said.
PNG officials said the defence deal was about ensuring the country's military met "modern-day standards".
Pacific Minister Pat Conroy said the details of the treaty would ultimately set up the legal framework for greater security co-operation.
"That could include, hypothetically, allowing more visits by Australian naval vessels or Papua New Guinea naval vessels to Australia, it could include greater military co-operation in training," he said.
PNG soldiers supported Australian communities during the bushfire crisis in 2020.
Mr Albanese said the two nations had a leadership role on climate change in the Pacific.
"There is not a moment to waste. It is up to our generation to protect the precious and unique natural environment of our rainforests, reefs and coasts," he said.
"To build - and plan - our infrastructure so our communities are more resilient and better prepared for natural disasters."
He also urged the region to continue pushing into clean energy technology and "grasp the transformative economic benefits".
Australia provides $600 million in development assistance to PNG each year, with defence cooperation running at about $50 million, including the provision of four patrol boats.