Unexpected Chinese naval activities in the Tasman Sea that forced commercial airlines to divert from possible live fire exercises, have sent top New Zealand and Australian politicians seeking answers and information.

An Emirates flight from Sydney to Christchurch was directly warned by the Chinese military to avoid an area of airspace on Friday morning, before Chinese vessels were believed to have conducted live fire exercises.

That warning - to flight EA3HJ - was issued around 11am, Sydney time.

Commercial pilots have been warned to avoid an area of airspace between Australia and New Zealand because of fears that Chinese naval vessels in the area were conducting live fire military drills.

The ABC has confirmed with Australian authorities that formal advice has been issued by air traffic controllers, which prompted several international flights to divert course.

The Chinese vessels were believed to be conducting the drills without notice, 340 nautical miles (670km) south-east of Sydney, in international waters.

The ABC understands the Chinese vessels were seen deploying a floating target, changing formation and then resetting formation consistent with a live fire event.

However, it is understood the Australian military did not observe the vessels firing on the target.

New Zealand Minister of Defence Judith Collins said there had been no confirmation that a live firing event happened, and her primary concern was the safety of our people, vessels and aircraft - but there was no ongoing danger to New Zealand.

However, Collins said Australia and New Zealand are working closely together to monitor the Task Group in the Tasman Sea, and to gather information on the event.

Chinese foreign ministry spokesman Guo Jiakun said China had followed international law.

"The [People's Liberation Army] Southern Theatre Command organised the Chinese fleet to conduct a far seas exercise," he said.

"The drill was carried out in a safe, standard and professional manner in accordance with the relevant international law and international practice."

In a statement, Air New Zealand told RNZ it "has modified flight paths as needed to avoid the area, with no impact on our operations".

An Emirates spokesperson told RNZ: "When a change in air space activity was detected, the flight deck crew on EK 412 (21 February) made a slight routing deviation as per standard industry protocol and in conjunction with ATC [Air Traffic Control], to maintain optimal safety margins.

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• Australian and New Zealand militaries monitoring Chinese warships off Australian coast
• NZ Defence Force says 'no notice given' from China about navy ships in the Tasman Sea

"Emirates uses advanced flight planning systems that optimise each route, carefully considering several factors to ensure a safe and smooth journey. Our crew also have rigourous protocols to maintain vigilance during operations."

Qantas and its subsidiary Jetstar told RNZ they are working with the Australian government to monitor the situation.

Wong to meet Chinese counterpart, Albanese discusses with Luxon

Australian Prime Minister Anthony Albanese said he had spoken with Prime Minister Christopher Luxon on Friday afternoon, as well as with the Australian chief of defence, Defence Minister Richard Marles and the foreign minister.

He would not be drawn on whether the matter concerned him.

"This is activity that has occurred in waters consistent with international law," Albanese said.

"There has been no risk of danger to any Australian assets or New Zealand assets."

Albanese said the vessels issued an alert they would be conducting exercises, including potential live fire.

He repeated that it was not clear whether a live firing had occurred.

This Jiangkai-class frigate Hengyang was among the Chinese flotilla sailing east of Sydney. Photo: ABC / Department of Defence

However, Marles told ABC Radio Perth: "We weren't notified by China, we became aware of the issue during the course of the day."

"What China did was put out a notification that it was intending to engage in live fire, and by that I mean a broadcast that was picked up by airlines, literally commercial planes that were flying across the Tasman."

Marles said the vessels had complied with international law but would usually be expected to give 12 to 24 hours' notice, "and so I can understand why this was probably ... very disconcerting for the airlines".

The incident comes just five days after a meeting between Australian Air Marshal Robert Chipman and senior Chinese military leader General Xu Qiling in Beijing - the first such meeting since 2019.

The ABC understands Chinese military had officials told Australia that they had cancelled live fire exercises by the warships which they had earlier planned to conduct ahead of that meeting - so as not to disrupt the dialogue. But they did not discuss any future potential exercises.

Australian Foreign Minister Penny Wong is expected to meet her Chinese counterpart Wang Yi on Friday evening.

She told ABC's Afternoon Briefing the vessels were being monitored.

"We will be discussing this with the Chinese, and we already have at official level - in relation to the notice given and the transparency provided in relation to these exercises, particularly the live fire exercises," Senator Wong said.

"We are aware of this task group, we are monitoring this task group very closely. It is, as I understand it, operating in international waters."

Coalition accuses Albanese of 'weakness'

Australia's Shadow Defence Minister Andrew Hastie was quick to describe Albanese's reaction as "weak".

"The Chinese government has built a blue-water navy to project power into the Pacific region. They are now using gunboat diplomacy to test US allies like Australia," Hastie said.

"When will the prime minister and his defence minister stand up for the Australian national interest and insist on mutual respect from their Chinese counterparts?

"Labor's silence on China's gunboat diplomacy - which is now impacting commercial flights - speaks volumes."

The Australian and International Pilots Association's vice president, Captain Steve Cornell, said the vessel activity was "inconvenient".

"Whilst it was unusual to have Chinese warships in this part of the world, pilots often have to contend with obstacles to safe navigation, whether that be from military exercises such as this or other events like rocket launches, space debris or volcanic eruptions," he said.

"That being said, it's a big bit of ocean and you would think that they could have parked somewhere less inconvenient whilst they flexed their muscles."

New Zealand Civil Aviation Authority spokesperson Mike Hill said it is aware of the advice issued by Airservices Australia, and if there are any known issues in New Zealand's domestic airspace, then pilots are usually told via a NOTAM (Notice to Airmen) update.

Vessels loiter off Australian coast

On Thursday, Australia's Defence Minister Richard Marles said Australian ships and aircraft were working "very closely" with New Zealand's military to monitor a Chinese naval taskforce transiting south-east off the east coast of Australia.

An earlier report from Washington in the UK's Financial Times newspaper said the flotilla was around 150 nautical miles (277km) east of Sydney.

The Australian Defence Department revealed last week the Chinese naval taskforce was being monitored in the Coral Sea, north-east of Queensland but within Australia's exclusive economic zone.

The department said the Chinese vessels were the Jiangki-class frigate Hengyang, the Renhai-class cruiser Zunyi, and the Fuchi-class replenishment vessel Weishanhu.

Australian Defence also confirmed last week a Chinese fighter had released flares in front of an Australian military plane, in what it described as an "unsafe and unprofessional" interaction.