Prime Minister Anthony Albanese has left Papua New Guinea without securing a landmark defence treaty.

Instead, the PM and his PNG counterpart James Marape have signed a non-binding communiqué, agreeing to keep advancing the treaty process.

It marks the second Pacific setback for Australia this month, with a $500 million security and economic deal with Vanuatu remaining unsigned.

• Guest: Michaelia Cash, Shadow Minister for Foreign Affairs and Liberal Senator for Western Australia
• Producers: Teodora Agarici and Lexie Jeuniewic