Negotiations for the Pacific regional trade agreement PACER Plus have concluded in Australia after eight years of planning.
The 14 countries participating will sign the agreement in Tonga in June.
PACER Plus is expected to enhance the economic development of Pacific island countries through greater regional trade and economic integration with Australia and New Zealand.
The New Zealand trade minister, Todd McClay, said the deal included a $US38 million development package for Pacific island countries to increase their export capacity.
"This is a development and trade agreement and we recognise whilst trade will provide much more for Pacific island economies, at the same time we have to help them get ready for some of the opportunities and benefits the agreement will deliver," he said.
While parties to the agreement already had duty free access for exports to Australia and New Zealand, Mr McClay said the deal allowed Pacific island countries to gradually phase out tariffs on imports in recognition of the vulnerable nature of their economies.
Critics of PACER Plus said the deal would deprive tariff revenue from Pacific island countries for essential services.
But Mr McClay said the deal was as much about development as it was about trade.
Notably absent from the conclusion of negotiations were representatives from Papua New Guinea and Fiji, after both countries pulled out of the agreement.
The deal includes an expedited process for countries who are members of the Pacific Islands Forum to join.
The 14 countries participating in PACER Plus are New Zealand, Australia, Cook Islands, Federated States of Micronesia, Nauru, Kiribati, Niue, Palau, Republic of Marshall Islands, Samoa, Solomon Islands, Tonga, Tuvalu, and Vanuatu.