The United States should view China's growing role in the Pacific as grounds for cooperation rather than concern, a top Chinese official said Friday, amid anxiety over Beijing's new assertiveness.

Washington and China's neighbours have expressed increasing fears about Beijing's claims in the South China Sea, military spending and new high-tech equipment, including an aircraft carrier that trialled last month.

But Chinese Vice Foreign Minister Cui Tiankai, speaking on the sidelines of the Pacific Islands Forum in Auckland, sought to ease the concerns.

"We are just part of the Pacific region, that's a geographical fact, nobody can change it -- China's also part of Asia, that's also quite true," Cui said.

He said Washington and Beijing shared a common interest in helping Pacific island nations cope with issues such as climate change and economic development, so they should work together.

China has become increasingly active in impoverished Pacific island nations in recent years, offering "soft loans" on easy credit terms and providing aid for projects such as hospitals and roads.

However, Washington has viewed China's involvement with suspicion and responded by increasing its own diplomatic presence in the region.

Asked if China wanted to cooperate more with the United States in the Pacific, Cui replied: "I would certainly hope so.

"Of course, the United States is on the other side of the Pacific, so I don't think the Pacific Ocean is something that should separate us, China and the US," he said.

"Rather, I would hope that the Pacific Ocean would be kind of a link to bring us together... I don't know why anyone should have any reservations about China's role in the Pacific, we're just part of it."

In a report two weeks ago, the Pentagon said China was increasingly focused on naval power and had invested in high-tech weaponry that would extend its reach in the Pacific and beyond -- claims Beijing dismissed as "groundless".

China's testing of its first aircraft carrier last month has sparked global concern, as has its growing emphasis on securing strategic shipping lanes and mineral-rich areas in the South China Sea.

Beijing claims sovereign rights to almost all of that maritime area, although several Southeast Asian countries have competing claims.

China announced earlier this year that military spending would rise to 601.1 billion yuan ($91.7 billion) in 2011 and also said it was developing its first stealth fighter jet.

China stresses the "defensive" nature of its spending. But a government white paper this week also highlighted its so-called "core interests" of territorial integrity and national reunification with self-governing Taiwan.

US Secretary of State Hillary Clinton last month warned against budget cuts in Washington that would lessen US influence in the Pacific at a time when China's power was rising.

"We are a Pacific power... we can't be abruptly pulling back or pulling out when we know we face some long-term challenges about how we are going to cope with what the rise of China means," she said.

Washington demonstrated its intent by sending a top-level delegation of around 50 officials to the annual PIF summit in Auckland.

Commenting on the size of the US delegation, which was more than five times larger than Beijing's, Cui joked: "Now I think I understand better why they have to talk about this budget deficit."