A Massey University academic says the uncertainty over the US Agency for International Development (USAID) will have implications for the Pacific region.
Donald Trump is considering significantly reducing the size of the USAID's workforce for efficiency purposes.
USAID, the world's largest aid agency, delivers billions of dollars in international aid annually.
Dr Anna Powles from Massey's Centre for Defence and Security said the agency provides about US$3.4 billion (NZ$6b) to the Pacific.
"The Pacific islands is one of the most aid-dependent regions in the world. 'There will obviously be implications for the region, particularly across those programmes such as the delivery of antiviral therapy for HIV and AIDS, tuberculosis, malaria.''
She also said it could affect newer programmes, such as the removal of Second World War ordnance, governance and climate change.
Powles said it was clear the US security footprint in the region will not diminish, but that it will impact the credibility of the US in the region.
''Under former President Biden the US sought to advance a rhetoric that the US was back in the Pacific, here to stay and that it was a credible partner. This will really undermine that rhetoric.''
Powles said it was entirely possible the US may say to New Zealand that it should be doing more in the region.
''We know that is a very common refrain from Trump - that allies and partners need to step up and do more in the region and globally.
"The insecurity that this is creating in the region over the impact on much smaller, but key programmes is something which is concerning everyone deeply across the Pacific.''