* New Zealand buys four P-8 long-range maritime patrol planes
* Deal valued at NZ$2.34 billion
* New aircraft to boost maritime surveillance in Pacific
* China urges NZ to "redress wrong deeds and actions" (Adds China foreign ministry comment in paragraphs 10, 11)
By Charlotte Greenfield
WELLINGTON, July 9 (Reuters) - New Zealand has agreed to buy four Boeing P-8A Poseidon maritime patrol planes, Defence Minister Ron Mark said on Monday, strengthening surveillance capabilities as it works to counter the rise of new powers, such as China.
New Zealand is responsible for patrol and rescue missions in an area of the Pacific Ocean bigger than Europe and plans to step up its engagement in the South Pacific, where it is losing sway over small island nations to China.
Mark said the aircraft were acquired from the United States through its foreign military sales programme and would cost NZ$2.34 billion ($1.6 billion), including training costs. They would be operational in 2023.
New Zealand's military had been looking to replace its ageing P-3 Orion fleet, and the upgrade pulls it in line with the capabilities of its Five Eyes intelligence-sharing partners - Australia, Canada, the United Kingdom and the United States.
"Maintaining maritime patrol capacity is essential for new Zealand's national security and for our ability to contribute to global security efforts," Mark told reporters.
On Friday, New Zealand released a defence policy statement warning that China's rising influence in the South Pacific could undermine regional stability.
It also alluded to tension in the contested South China Sea, which Beijing largely claims as its own, in the face of competing claims from several Southeast Asian nations.
Acting Prime Minister Winston Peters said the report had drawn a complaint from China.
"The Chinese have made clear to our ambassador in Beijing their concerns about that, as their ambassador here has made her concerns known to Foreign Affairs," he told reporters.
When asked on Monday about the purchase, China's foreign ministry spokeswoman, Hua Chunying, said China's development did not pose a threat to anyone.
"We urge New Zealand to correctly understand China and our relations with New Zealand, redress wrong deeds and actions, and do more that is beneficial to mutual trust and co-operation between China and New Zealand," she told a regular briefing.
The Chinese embassy in Wellington did not immediately respond to a request for comment. New Zealand's foreign ministry said it had been in touch with Chinese diplomats.
"New Zealand and China have a mature and resilient relationship and are able to discuss a range of foreign policy and national security topics including where we have different views," a foreign ministry spokeswoman said.
The Poseidon, widely considered the world's most advanced aircraft in anti-submarine warfare, signals New Zealand's readiness to help allies counter China in the South China Sea, analysts said.
"As a defence partner, you need assets. It is no good saying that you uphold the international rules-based order, you need something that will be useful for Australia and the United States," said Euan Graham, a defence policy expert at Sydney's Lowy Institute.
"The most obvious way is to have the same system, the P-8."
Australia has committed to buy 15 Poseidon planes to replace its Orion aircraft, set to be withdrawn from service next year. Boeing says 85 Poseidons now operate worldwide.
Last month, South Korea said it would buy the Poseidon, as it strengthens anti-submarine capabilities in the face of the threat from neighbouring North Korea's submarine-launched ballistic missiles.
Mark said New Zealand could consider more purchases of maritime surveillance technology as part of a review due by year-end.
"The complementary capability will consider smaller manned aircraft, remotely piloted aircraft systems or satellites, for additional maritime surveillance tasks," he said. ($1=1.4622 New Zealand dollars) (Reporting by Charlotte Greenfield in WELLINGTON; Jamie Freed in SINGAPORE and Colin Packham in SYDNEY; Additional reporting by Christian Shepherd in BEIJING; Editing by Clarence Fernandez, Darren Schuettler and Neil Fullick)