SINGAPORE (BLOOMBERG) - The US is expanding a programme to help South Pacific nations improve intelligence gathering, a top military official said, as China has increased its influence among small island countries.

Concerns are rising that Beijing's leaders are seeking to win through coercion the allegiance of islands typically aligned with the United States, Admiral Philip Davidson, commander of the US Indo-Pacific Command, told a security forum in Singapore on Saturday (June 1). The region played a key role in World War II and remains strategically important as Western powers seek to maintain open sea lines and stability.

China has stepped up state-directed economic investment into the Pacific islands region, which is home to more than a dozen nations, including Fiji, Niue and Nauru, scattered across thousands of kilometres of ocean.

That has prompted the US and its close ally Australia to step up engagement with those countries.

The US is adding more defence attaches in the region, Adm Davidson said.

"America has expanded its maritime security initiative for the South Pacific," Adm Davidson said. "This is a proven programme to improve patrol craft and increase intelligence gathering, train our partners, and share information to support sovereign enforcement of exclusive economic zones."

Adm Davidson also brought up environmental concerns, including illegal and unregulated fishing that is depleting ocean stocks and causing environmental degradation.

Acting Defence Secretary Patrick Shanahan ripped into China at the gathering earlier in the day, saying Beijing is behind bad behaviour that "sows distrust" in Asia.

Still, he also said the US and China would eventually resolve their differences, downplaying the significance of escalating trade tensions.