The United States is not in the Pacific to compete with anyone, a senior Trump administration figure says.
US Secretary of the Interior David Bernhardt told a session at the Pacific Islands Forum his country had an "incredible relationship" with the region, going back to World War II.
"That is built on a fundamental belief of liberty, of freedom, of common values and a legacy of sacrifice and commitment to the region," he said.
"I think that is quite significant and I don't think we need to compete with anybody."
American and Chinese officials addressed a session at the forum in Tuvalu on Friday, just as regional leaders including Scott Morrison and Jacinda Ardern jetted out.
China has been investing heavily in terms of aid and other projects in the region in recent years, and is now leading the US - but still lags Australia by a long way.
Some analysts say a drop in focus from the US on the region has left it open for China to play an increasingly assertive role.
Senior US diplomat Sandra Oudkirk said the Trump administration was planning to increase its presence in the region, focusing on "diplomacy, development and defence".
"At its core, what we're looking to do on the economic side is to support market economies, connectivity, infrastructure projects that are sustainable, that don't burden communities and countries with debt or compromised sovereignty," she said.
China's special envoy for the Pacific, Wang Xuefeng, said his country would "always be a good friend, partner and brother of Pacific island countries".
"China believes that all countries, big or small, are equals," he said.
He said China was committed to reducing carbon emissions and helping other countries deal with climate change.
Taiwan's minister of foreign affairs Joseph Wu said it was important like-minded countries like his, the US and Australia made sure the Pacific remained free and open.
"China is trying to increase its presence in the region for sure. But I think those countries that have received aid from Taiwan, they understand that what we try to do is benefit the people directly," he told AAP.
"We have no problem when China is continuing to increase their presence in the region, our allies are still deeply committed to us."
The Pacific leaders agreed to seek a meeting with US President Donald Trump over the "nuclear testing legacy" in their region, which Mr Bernhardt said he would take to the White House.
"He (Mr Trump) took a meeting earlier this year with folks from this region so I'd have to see what the request looks like and go from there," he said.