Baron Waqa [Source: AAP]

An attempt by Pacific Islands Forum leaders to revisit a unity pact has sparked a walk-out by Nauru, showing tensions remain close to the surface at the pivotal regional body.

The Micronesian nation’s delegation left a plenary session on Thursday (AEDT) to protest a discussion over its preferred candidate for the position of Pacific Islands Forum (PIF) secretary general, Baron Waqa.

The rupture recalled a damaging split last year which threatened the viability of the body.

However, it’s understood Nauru President David Adeang has since calmed and will take his place at the all-important leader’s retreat on Friday.

Leaders from the Pacific have gathered in Rarotonga this week for the annual PIF leaders meeting.

The 18-nation grouping is a combustible forum, given it represents nations as different as regional heavyweights Australia and New Zealand, and micro-states like Niue and Tuvalu.

The body is of huge importance to Australia, with Prime Minister Anthony Albanese investing a mighty diplomatic effort into maintaining its place as the Pacific’s primary decision-making group.

Australia pays the lion’s share to fund its operations, while Foreign Minister Penny Wong has visited every PIF member since taking office.

Mr Albanese is representing Australia at the gathering, which is missing leaders from four of the biggest six members: Papua New Guinea, Solomon Islands, Vanuatu and New Zealand.

The centrepiece is the leaders’ retreat, where one representative from each nation discusses the region’s biggest issues behind closed doors in a day-long meeting.

This year, a number of issues have been added to the retreat agenda at the 11th hour.

One of those is the Suva Agreement, which caused Nauru’s walk-out.

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