By Lucy Craymer, Greg Torode, and Yimou Lee

WELLINGTON/HONG KONG/TAIPEI, Nov 27 – The largest ship in the New Zealand navy, the oiler HMNZS Aotearoa, made an uncommon journey through the Taiwan Strait earlier this month, according to Defence Minister Judith Collins.

A knowledgeable source indicated that Chinese forces tracked and followed the ship during its passage through the strait.

Collins did not elaborate on any activities by China but confirmed that the transit adhered to international law. She stated, "This includes exercising the right to freedom of navigation, as guaranteed under the United Nations Convention of the Law of the Sea," in an email.

The Aotearoa traveled from the South China Sea to the North Asian area through the Taiwan Strait on November 5, as noted by the minister.

This mission has not been reported publicly before.

China claims Taiwan, which operates as a democracy, as part of its territory and asserts it has sovereignty over the strait. Meanwhile, both the U.S. and Taiwan maintain that the strait is an international waterway, a crucial trade route for nearly half of the world's container ships.

The last known transit of New Zealand's navy through the strait, accompanied by an Australian navy ship, occurred in September of last year. This marked the first New Zealand naval ship crossing the strait since 2017.

According to the source, during the Aotearoa's transit, Chinese vessels and aircraft kept watch, with Chinese jets even performing simulated attacks.

The Chinese defense ministry did not respond to requests for comments.

Taiwan's defense ministry stated that its armed forces "maintain comprehensive awareness of all military activities across the region and respond appropriately, ensuring national defense security," without providing further details.

The transit occurred alongside Taiwan reporting that on November 6, China conducted a "joint combat readiness patrol" around the island, involving J-16 fighter jets, focusing on the strait and the area to Taiwan’s southwest.

The Aotearoa, built in South Korea, is not armed with heavy weaponry but can carry a helicopter and is used for fuel and supply replenishment at sea.

Last month, the New Zealand Defence Force mentioned that the ship was planning to participate in United Nations sanctions enforcement missions related to North Korea near Japan.

New Zealand does not have formal diplomatic relations with Taiwan, like most countries; however, Taipei regards it as an important democratic partner, and both maintain unofficial embassies in each other's capitals.

Additionally, New Zealand is one of only two major countries, alongside Singapore, that has a free trade agreement with Taiwan.

U.S. warships navigate through the strait every few months, often provoking criticism from Beijing, while allies like Canada and the UK have also made occasional transits.

China, which has not ruled out the use of force to assert control over Taiwan, has significantly increased military operations around the island over the past five years, including conducting war games.

Taiwan's democratically elected government rejects Beijing's claims of sovereignty.