Pacific leaders are showing their resolve to keep their region nuclear-free, raising concerns at the Pacific Islands Forum over AUKUS and Japan’s release of Fukushima power plant wastewater into the ocean.

Pacific Islands Forum (PIF) leaders will also revisit the Suva Agreement, a regional unity pact that saved the organisation from collapse last year, at this year’s talks.

Prime Minister Anthony Albanese has joined Pacific leaders in the Cook Islands this week for the annual meeting of regional powerbrokers.

On Thursday (AEDT), he will board a flight to the idyllic island of Aitutaki, sailing around the picturesque turquoise lagoon as the group thrashes out the region’s top issues at the leaders’ retreat.

Top of the list for the retreat is climate change, which is intensifying cyclones in the region and threatens to raise sea levels, jeopardising Pacific communities.

Leaders have told AAP a number of issues have been put onto the retreat agenda as late inclusions, including nuclear concerns and the imminent PIF leadership transition.

Current secretary-general Henry Puna is due to be replaced by Baron Waqa, a controversial former Nauru president who was deeply involved in Australia’s asylum seeker processing centre in his Pacific nation.

During his tenure, he sacked the country’s judiciary, led a crackdown on media, and has also been linked to an Australian Federal Police corruption probe into phosphate dealer Getax, leading critics to declare him unfit to lead the regional body.

However, his candidacy is crucial for regional unity.

Last year, Micronesian nation Kiribati announced its intention to leave PIF, upset at a lack of power-sharing among members, triggering unity talks and a deal to allow Micronesia to name the next secretary-general, with Waqa chosen.

That deal, the Suva Agreement, will be revisited in the closed-door leaders-only retreat.

“The Suva Agreement has been raised for late inclusion. It can be discussed privately on the retreat,” Niue Premier Dalton Tagelagi told AAP.

Fiji’s Prime Minister Sitiveni Rabuka and Puna also confirmed Waqa’s candidacy would be discussed.

“No comment now. It is still to be talked over by the leaders,” Puna told AAP.

The survival and success of PIF is of the utmost importance to Australia, which has put huge diplomatic resources into the body under Albanese’s tenure.

Albanese describes the region as family and hopes deep engagement can ensure close ties, rather than nations throwing in their lot with China, causing strategic concerns.

A pair of nuclear issues will also grace the retreat agenda.

The Pacific is stridently nuclear-free, a legacy of the region’s painful history with testing of nuclear weapons by the United States, United Kingdom and France.

Australia’s AUKUS deal to obtain nuclear-powered submarines raises concern among many, given the sensitivity of nuclear issues.

PIF chair and Cook Islands Prime Minister Mark Brown has suggested the time could have come to “reinvigorate” the Treaty of Rarotonga, the nuclear weapons-free pact signed during the Cold War.

The legacy of another nuclear incident – the 2011 Fukushima power plant disaster – also hangs over the Pacific.

Japan is releasing treated wastewater from the power plant, insisting it is safe to do so, with an International Atomic Energy Agency report as proof.

Australia and New Zealand accept those guarantees, but a growing number of Pacific nations hold concerns, including Polynesian and Melanesian blocs.

At the PIF summit, Rabuka is championing another initiative: declaring the Pacific an “ocean of peace”.

That could feed into Mr Brown’s proposed reinvigoration of the Treaty of Rarotonga.

– AAP