Australia’s defence chief has admitted it missed a warning about a Chinese warship live firing exercise – contradicting Prime Minster Anthony Albanese’s timeline of when it was known about.

Admiral David Johnston told a Senate estimates committee on Wednesday that a warning from a New Zealand warship that Australia was relying on to track three Chinese warships off Australia’s east coast was received in Canberra at around 11am last Friday. 

This was 90 minutes after the firing started and 50 minutes after a similar warning was reported by a Virgin Australia’ airline pilot.

Admiral Johnston said it hadn’t been possible to detect the short range radio signal used by Chinese warships in the warning, despite the ADF surveilling the vessels for several days prior.

Later on Wednesday, Mr Albanese said the New Zealand warning came ‘at around the same time’ as the pilot’s notification to Airservices Australia, which had been passed to Defence 50 minutes earlier.

That comment, along with saying last week that China gave notice of the exercise ‘in accordance with practice’, has sparked fresh claims from the Opposition that the Prime Minister misled the public.

Admiral Johnston also revealed at the Senate estimates that it’s ‘possible’ a Chinese nuclear-powered submarine may have been lurking underneath underneath the warships.

Admiral  David Johnston (pictured on Wednesday) said it hadn’t been possible to detect the short range radio signal used by Chinese warships in the warning

A warning from a New Zealand warship that Australia was relying on to track three Chinese warships (one pictured) off Australia’s east coast was received in Canberra at around 11am last Friday

‘It is possible,’ Admiral Johnston said. 

‘Task groups occasionally do deploy with submarines, but not always. I can’t be definitive on whether that’s the case.’

He said China had given ‘inadequate notification’ of the ‘clearly disruptive’ live weapons drill, which caused 49 aircraft diversions.

Opposition Home Affairs spokesman James Paterson said the delayed notice meant there was no advance warning of the exercise in international waters.

‘It’s not really notification of an upcoming exercise if we only find out about it after it has commenced, is it,’ he told Senate estimates.

There are mounting calls from the Opposition to explain why the government took so long to find out about the exercise.

‘It’s remarkable that Australia was relying on civilian aircraft for early warning about military exercises by a formidable foreign task group in our region,’ Senator Patterson told The Australian.

‘The Prime Minister’s attempt to mislead the public by suggesting there was notice given by the People’s Liberation Army – Navy (PLA-N) and it was reported through military channels in a timely way is yet more evidence of his weak leadership.

The Chinese live-fire drill fiasco has sparked claims Prime Minister Anthony Albanese (pictured) mislead the public

‘He should be honest, admit we were never notified, and call out this malign behaviour instead of making excuses for the PLA-N.’

Opposition leader Peter Dutton said the Prime Minister has some explaining to do.

‘If there was an incursion across into our waters and Defence didn’t know about it, or the Defence Minister didn’t know about it, we need to ask those questions and they should be answered,’ he said.

‘The Prime Minister should stand up and explain what is a very significant event, but at the moment, obviously the Prime Minister hasn’t done that, and his story seems to be at odds with the version given by the Chief of the Defence Force in estimates. 

‘These are very serious questions that the Prime Minister needs to answer.’ 

Greens senator David Shoebridge also slammed the Government on the issue, saying he was ‘trying to work out how it is with a $55.7billion budget, we find out from a Virgin pilot and a delayed notification from New Zealand’.

Defence Minister Richard Marles told Melbourne radio that China had not yet given a ‘satisfactory answer’ for the lack of notice for the drill, which was repeated on Saturday. 

The fallout from last Friday’s Chinese warship live firing exercise continues

‘The moment that this (Chinese) task group came near Australia, I authorised an unprecedented level of surveillance. We’ve been doing that in combination with our ally, in respect of New Zealand,’ Mr Marles said.

‘It was the New Zealand frigate that was doing the shadowing work at that time. So we both heard from New Zealand and from the commercial airlines around this.’

The revelations come as Foreign Minister Penny Wong prepares to address the nation on Thursday about the ‘unprecedented’ global challenges about Australia is facing.

‘Bullies are threatening to use nuclear weapons, authoritarianism is spreading … institutions we built are being eroded, and rules we wrote are being challenged,’ she will say.