Melbourne, Feb 21 (AP) Airliners were over the Tasman Sea crossing between Australia and New Zealand when the Chinese navy warned they were flying over a secret live-fire exercise, Australian Defence Minister Richard Marles said on Friday.

Regulator Airservices Australia warned commercial pilots of a potential hazard in airspace between the countries as three Chinese warships conducted exercises off the Australian east coast.

But Marles said Australian authorities only learned about China's live-firing plans in international waters midway between Australia and New Zealand from the airlines.

“To be clear, we weren't notified by China,” Marles told Australian Broadcasting Corp. radio in Perth.

“What China did was put out a notification that it was intending to engage in live firing. By that, I mean a broadcast that was picked up by airlines or literally ... commercial planes that were flying across the Tasman,” Marles said.

“This was very disconcerting for the planes that were flying,” he added.

Three flights from Sydney bound for the New Zealand cities of Christchurch and Queenstown were in the air on Friday morning before they were first warned by a Chinese warship of a live-fire exercise, media reported.

All changed course. The three airlines involved, Emirates, Qantas and Virgin Australia, did not comment.

Marles said the Australian navy would typically give 12 to 24 hours' notice of a live-firing exercise to allow airlines time to properly plan around it.

But he said all flights were able to divert and no one was put in danger.

The warships — frigate Hengyang, cruiser Zunyi and replenishment vessel Weishanhu — are exercising a freedom of navigation in international waters off the Australian east coast of a kind that angers Beijing when exercised by the Australian military in the disputed South China Sea.

During a regular Chinese foreign ministry briefing on Friday, spokesperson Guo Jiakun said China's military had organized its fleet to conduct high seas exercises. “The drill was carried out in a safe, standard and professional manner in compliance with relevant international law and international practice” Guo said.

Australian defence officials were uncertain whether any live fire of weapons had occurred. The risk had since passed, Australian Prime Minister Anthony Albanese said.

“There was no imminent risk of danger to any Australian assets or New Zealand assets,” Albanese told reporters, citing information from his Defence Ministry.

New Zealand's aviation regulator did not issue warnings. The Civil Aviation Authority said it was “aware” of the Australian advice, according to a statement. The authority did not explain its decision.

Australian Foreign Minister Penny Wong said she would discuss the air service disruption when she meets her Chinese counterpart Wang Yi at a G20 ministers meeting underway in South Africa.

Flight monitoring websites showed multiple flights had avoided an area between Australia and New Zealand.

Air New Zealand, the country's national carrier, said in a statement it had “modified flight paths as needed to avoid the area, with no impact on our operations".

Australian and New Zealand military ships and P-8 Poseidon surveillance planes have been monitoring the Chinese warships for days.

Chinese warships rarely venture so far south in a deployment regarded as a demonstration of the Chinese navy's growing size and capabilities.

Captain Steve Cornell, vice president of the Australian and International Pilots Association, which represents Qantas pilots, was critical of where the Chinese chose to hold their exercise.

“It's a big bit of ocean and you would think that they could have parked somewhere less inconvenient whilst they flexed their muscles,” he added.

The Chinese exercise was legal and took place in international waters outside Australia's exclusive economic zone, Albanese said. (AP) PY PY