Numerous problems have been identified on Australian-built patrol boats gifted to Pacific Island nations, prompting the Defence Department to issue advice on how to "minimise risk" for the countries that operate them.

West Australian-based shipbuilder Austal accepted blame and will pay to fix the defects discovered with its Guardian class patrol boats, including a potential fault in the exhaust system.

Since 2018, Australia has delivered 15 of the vessels to Pacific nations under the $2.1 billion Pacific Maritime Security Program (PMSP) to help deal with challenges such as illegal fishing.

In a statement, the Defence Department said it recently advised the government of an "issue" in the Guardian class patrol boats involving a potential fault in the exhaust system.

The ABC understands the defect is connected to the boat's stern tube system, a similar problem that was encountered with Austal's Cape class patrol boats several years ago.

The department has also publicly acknowledged for the first time other longer-known faults with the Guardian class fleet, including cracking in the coupling between the engine and the gearbox, and problems with ventilation in the sick bays.

"Under the PMSP, the Guardian Class Patrol Boats are the sovereign property of individual Pacific Island nations, and each nation will make its own decision on whether they choose to continue to operate their vessels, or pause operations," the department said in a statement.

"Austal and Defence representatives soon will travel to Pacific Island nations to assess all vessels and work with Pacific Island countries on temporary rectification measures ahead of a longer-term solution."

Defence Industry Minister Pat Conroy said his department was working closely with regional neighbours on how to deal with the problems.

"The safety of our Pacific partners is of utmost importance, and we are committed to working through all challenges together to make sure these boats are safe and operational," Mr Conroy said.

"We understand how important these vessels are for Australia and our partners in the Pacific. The Guardian patrol boats play a critical role in maritime surveillance activities as well as detecting and deterring illegal, unreported and unregulated fishing."

Mr Conroy, who also serves as Minister for the Pacific, took aim at the previous government for keeping the problems hidden and unresolved.

"This is the latest example of [how] the previous Liberal government was all announcement and no follow-through when it came to defence projects," he said.

Last year the ABC revealed poor quality aluminium imported from China had delayed Austal's delivery of new $350 million evolved Cape class patrol boats to the Royal Australian Navy.

Back in 2017 the ABC also revealed problems with Austal's $330 million Cape class fleet that affected operations of the Australian Border Force.

In recent years, several Pacific nations including Papua New Guinea, Samoa and Solomon Islands have damaged their Australian-gifted patrol boats during mishaps, such as running aground on reefs.