Prime Minister Yoshihiko Noda and the leaders of Australasian and Pacific island nations will discuss maritime concerns and disaster countermeasures at a summit in Okinawa this weekend, with a representative from the United States attending for the first time amid China's growing regional influence.

Noda is expected to pledge around $500 million (¥40 billion) in new official development assistance over the next three years and announce two disaster prevention initiatives that draw on the lessons of the Great East Japan Earthquake, government officials said.

Sixteen nations and one territory will be represented at the sixth Japan-Pacific Islands Forum summit Saturday and Sunday in the city of Nago, with maritime issues on the agenda for the first time as China ramps up its political, military and economic clout in the region, they said.

The issue will be referred to in a joint declaration to be adopted at the two-day summit, along with climate change, sustainable development, people exchanges and human security, an approach that places the safety of individuals at the center of security issues.

Dan Clune, principal deputy assistant secretary of the U.S. Department of State, will also attend the summit as Washington seeks to fend off China's growing threat to its leadership in the Asia-Pacific region.

The summit, hosted by Japan every three years and to be cochaired by Noda and Cook Islands Prime Minister Henry Puna, is of significant strategic importance to Japan: Twelve of the Pacific nations taking part hold votes that Tokyo is counting on in its pursuit of a permanent seat on the U.N. Security Council.