Australia and Indonesia will join forces to combat illegal fishing, drug trafficking and people smuggling under a wide-ranging maritime deal.
The two nations on Friday signed the new plan of action, which also indirectly addressed concerns about the South China Sea.
It followed talks between Foreign Minister Julie Bishop, Defence Minister Marise Payne and their Indonesian counterparts Retno Marsudi and Ryamizard Ryacudu in Sydney.
The annual ministerial meeting happened on the sidelines of the broader Australian and Association of South East Asian Nations (ASEAN) leaders' summit.
The agreement commits to 85 separate maritime activities, involving 17 different Australian agencies.
It aims to strengthen maritime security, combat transnational crime, improve search and rescue coordination and disaster risk management.
There will also be more team work on cleaning up marine environment pollution and scientific collaboration.
"This plan of action is a pragmatic series of steps that we can take together to ensure that our maritime surrounds are peaceful, stable and prosperous," Ms Bishop told reporters.
She alluded to concerns over the South China Sea, noting that Australia and Indonesia share similar views on the need to support, promote and defend the international and regional rules-based order.
"That order includes free and open trade between nations," Ms Bishop said.
"This plan of action goes some way to towards those ideals and also focuses on our fundamental belief in freedom of navigation and freedom of overflight in accordance with international law."
Ms Marsudi said southeast Asia had enjoyed an "ecosystem" of peace, stability and prosperity for 50 years and Australia played an important role in creating that.
"Our aim is to tap into opportunities while overcoming challenges including the non-traditional threat to our maritime security and safety," she told reporters.
The quartet also discussed the threat of foreign fighters returning to the region from the Middle East and the importance of boosting intelligence-sharing.
With the so-called Islamic State caliphate mostly crushed in Iraq and Syria, Australia and South East Asian countries are making sure they are ready to keep foreign fighters at bay.
Mr Ryacudu said about 1000 fighters had already returned to Indonesia.
There are hopes that boosting cooperation will ensure there is no repeat of last year's five month insurgency flare up in Marawi, the Philippines.
"We're are monitoring terrorism financing, social media and also the returnees who are coming in and out of Indonesia," he said.
Australia and Indonesia last month signed a new defence cooperation agreement in Perth.
Australian Associated Press