Fiji and the Solomon Islands have signed a maritime boundary agreement to set their shared ocean borders, and Niue and Tonga have begun steps toward the same.
The agreement was signed in Suva on the margins of the 51st Pacific Islands Forum (PIF) summit.
It clarifies the locations of both nations' intersecting maritime boundaries and zones and their rights and obligations according to United Nations Convention on the Law of the Sea.
Fijian prime minister Frank Bainimarama said the deal marked "a step toward a brighter and bluer future" for both countries.
The agreement established the boundaries as permanent, "irrespective of climate change-related sea-level rise and its potential impact on maritime boundaries."
Solomons prime minister Manasseh Sogavare said the agreement between the two countries celebrated a chapter about oceans in the Pacific Islands Forum's '2050 Blue Pacific Strategy'.
The strategy was expected to be adopted by Pacific Islands Forum members at this week's summit.
There are 48 shared or overlapping boundaries between countries in the Pacific, of which 35 are formalised in agreements.
There are now 12 outstanding bilateral boundaries and five high seas boundaries remaining to be declared.
-RNZ / Pacific News Service
Niue and Tonga begin steps toward establishing boundaries
Niue and Tonga have made an initial step toward also establishing formal boundaries between their two maritime zones.
The leaders of the countries met on the sidelines of the Pacific Islands Forum summit in Fiji this week.
In a statement, the Niue government said their premier Dalton Tagelagi spoke with Tongan prime minister Siaosi Sovaleni about the importance of the maritime boundary and discussed the establishment of formal diplomatic relations between the countries.
Tagelagi said the formal boundaries were critical for marine conservation, natural resource management, governance, peace and security.
He thanked Tonga for providing a patrol boat to assist when a Taiwanese fishing vessel ran aground on Niue's Beveridge Reef two months ago.
Niue also announced a support package to help Tonga recover from the Hunga Tonga-Hunga Ha'apai eruption, including almost $NZ70,000 to help with rebuilding.