The surveillance aircraft is bound for a US facility in Japan alongside Canadian military planes to monitor Pyonyang's vessels on the high seas.
"We do have a P-8A surveillance aircraft that is going to be working in the region to monitor compliance with sanctions," Prime Minister Malcolm Turnbull told reporters in Sydney on Saturday.
"That is part of our collaboration with partners in that exercise to enforce those UN sanctions, and it's very important that be done."
The United Nations has long suspected that North Korea has used illicit ship-to-ship transfers to try and evade sanctions imposed on the country for its nuclear weapons program.
"What has been occurring is that sanctions have been evaded by transferring materials from ship-to-ship and so obviously being able to surveil - to add to the surveillance of the area - enables that to be identified," Mr Turnbull said.
"And then, of course, those who are party to that, to be held responsible and brought to account."
Defence Minister Marise Payne welcomed North Korea's announcement of a halt to its ballistic missile and nuclear weapons testing, and on working towards the complete denuclearisation of the Korean Peninsula.
"However, along with our partners, we will continue to apply maximum pressure on North Korea until it takes concrete and verifiable steps to denuclearise," Senator Payne said in a statement.
"Australia will continue to work with our partners in the region to ensure the full implementation and strict enforcement of United Nations Security Council resolutions."
Foreign Minister Julie Bishop declined to comment on how long the P-8A Poseidon would remain in Japan, saying it was an operational matter.
