The United States will spend upwards of $US150 million ($NZ255 million) on projects and initiatives in the Pacific.

The US State Department said the Trump administration is reorienting Pacific relationships towards "championing US enterprise and investments", mirroring its approach to much of the developing world.

The State Department's second top diplomat, Christopher Landau, has been on the Pacific meeting circuit regularly since February, when leaders were invited to Honolulu to hobnob with US investors and military officers.

Its biggest spend is a fuel security deal that, pending US Congress, would dole out $US60m to fix up energy infrastructure and build storage capacity.

The big winners of the lolly scramble are the Cook Islands - with $US50 million for its Penhryn Atoll port, announced on Tuesday, and the Compact of Freely Associated States; Palau, Federated States of Micronesia and the Marshall Islands.

Palau, this year's Pacific Islands Forum leaders’ summit hosts, will walk away from the meeting with cash for a new hospital upgrade, support to test and clean its drinking water, and a co-chair role on a new US-backed Pacific Policing Forum.

The Marshall Islands will receive technical assistance to modernise its mobile network, and each of the Compact states will see the return of the US Peace Corp, the highly sought after band of American volunteers.

Tonga, which is subject to a harsh travel ban into the US, is being given feasibility studies for fuel storage and data centres.

A second Pacific investment summit in Honolulu has also been promised in early 2027.