New Zealand announced a $1.6 billion purchase of US military aircraft on Monday as it seeks to integrate its forces with US and Australian allies that are trying to counter a Chinese military buildup in the Pacific.

The purchase of the four Boeing P-8A Poseidon maritime patrol aircraft "strengthens the coalition Government's Pacific Reset by providing a maritime patrol capability with the significant range and endurance needed to assist our partners in the region," a statement from New Zealand Defense Minister Ron Mark said.

New Zealand's announcement comes on the heels of the release Friday of its Strategic Defense Policy Statement for 2018. In it, New Zealand warns of China's increasing influence in the Pacific, including its expanded military presence in the South China Sea, where Beijing is fortifying islands near some of the world's key shipping lanes.

The 40-page document says China is challenging the existing order in the region while also increasing its involvement and investment in Pacific island nations where New Zealand's influence has long held sway.

New Chinese policy priorities could potentially damage "human rights, arms control and non-proliferation efforts," it says.

Meanwhile, Australia and the US are trying to reinforce regional peace and stability with a focus on "maritime security and freedom of navigation," the document says.

Meshing with allies

Mark noted that the twin-engine P-8As, which can be used for submarine hunting as well as intelligence gathering and surveillance, are also in the inventories of the US, Australia and the United Kingdom.

Those nations, along with New Zealand and Canada, are part of the so-called Five Eyes alliance, which shares intelligence gained from spying activities.

"Maintaining a maritime patrol capability is essential for New Zealand's national security, and for our ability to contribute to global security efforts," Mark's statement said.

China on Monday blasted the "groundless accusations" in the New Zealand defense paper.

Foreign Ministry spokeswoman Hua Chunying said during Monday's press briefing that New Zealand needs to "correct its mistaken remarks and actions and do more to improve mutual trust and cooperation."

Beijing would not back off claims in the South China Sea nor pull back its development efforts elsewhere, Hua said.

"China's development has never threatened anyone else; instead, it has brought important opportunities for other countries," the spokeswoman said.

'Responsible international citizens'

Speaking at a news conference Monday announcing the P-8A deal, New Zealand's acting prime minister, Winston Peters, brushed off Chinese complaints about the defense policy statement.

"We're not here to make people happy. We're here to be responsible international citizens doing our best to preserve the neighborhood in which we live and to preserve our sovereignty," said Peters, New Zealand's foreign minister who is running the government while Prime Minister Jacinda Ardern is on maternity leave.

Monday's aircraft purchase and New Zealand's rationale for it were good news for Washington, which has been busy trying to strengthen its Pacific alliances in the face of what it sees as an increased Chinese threat.

New Zealand naval forces this month are participating in the US Navy's RIMPAC exercises, the world's largest naval drills.

Among the other nations in the Hawaii-headquartered war games are Vietnam, Malaysia and the Philippines, which all have claims in the South China Sea.

China was disinvited from the US-led exercises over its militarization of the South China Sea islands.

New Zealand, meanwhile, was given an expanded role in the 25-nation RIMPAC, serving as sea combat commander for the first time in 26 editions of the biennial war games.

Among the hardware New Zealand sent to RIMPAC are two P-3 Orion aircraft, the planes the P-8As will be replacing.

New Zealand expects the P-8As, which are based on Boeing's 737 airliner, to enter service in 2023.

Mark, the defense minister, said New Zealand would also be looking to acquire other smaller surveillance aircraft, including drones, to work in areas close to the island nation.

"This will free up the new P-8A fleet to fly more missions, in the South Pacific and further afield," he said.

-CNN