New Zealand would strongly oppose any militarisation of the Pacific, Prime Minister Jacinda Ardern has said after media reports China is eyeing a military base in Vanuatu.

Initial talks have already begun with Vanuatu, which could result in China establishing a major military presence and upsetting the delicate strategic balance in the region, Australia's Fairfax Media reported on Tuesday.

Chinese money has already helped finance a new wharf on the north island of Espiritu Santo, alongside an upgrade to the international airport.

Ms Ardern on Tuesday couldn't confirm the reports, but told reporters "we take a strong position in the Pacific against militarisation".

"That will be between those two sovereign nations and I can't comment on the validity of that," she said.

"But what I can say is we, of course, keep a watching eye on activity in the Pacific and that New Zealand is opposed to the militarisation of the Pacific generally."

The ability for China to dock warships and refuel on what would be their first Pacific base has rung alarm bells among Australian security chiefs, as well as US officials, who are said to be monitoring the situation, Fairfax reports.

Australian Foreign Minister Julie Bishop says she is confident of Australia's strong relationship with the island nation 1750km east of northern Australia.

Initial talks have already begun with Vanuatu, which could result in China establishing a major military presence and upsetting the delicate strategic balance in the region, Fairfax Media reported on Tuesday.

Chinese money has already helped finance a new wharf on the north island of Espiritu Santo, alongside an upgrade to the international airport.

The ability for China to dock warships and refuel on what would be their first Pacific base has rung alarm bells among Australian security chiefs, as well as New Zealand and US officials, who are said to be monitoring the situation, Fairfax says.

Ms Bishop said while China was investing in infrastructure around the world, in had to date only established one military base - in Djibouti in northern Africa.

"I'm not aware of a military offer being made by China to Vanuatu," she told ABC radio on Tuesday, noting the government of Vanuatu had also said there was no such proposal.

"We have very good relationships with Vanuatu and I remain confident that Australia is Vanuatu's strategic partner of choice."

China had been more engaged with the Pacific recently and its naval ships visited Vanuatu in 2017, but those sorts of visits were normal for all nations to conduct, Ms Bishop said.

The Lowy Institute's Pacific islands expert, Jonathan Pryke, says the new Luganville wharf development had "raised eyebrows in defence, intelligence and diplomatic circles" in Australia.

Ms Bishop said more infrastructure spending was needed in the Pacific but the key question was how it was invested and the terms of that investment.

But Vanuatu's high commissioner in Canberra, Kalfau Kaloris, was quoted as saying his country's foreign ministry was "not aware" of China's determination to build a permanent presence on the island.