Mr Dutton, US Attorney-General William Barr, acting US Homeland Security Secretary Kevin McAleenan and British Home Secretary Priti Patel have released a joint open letter to Facebook founder Mark Zuckerberg, warning the company about its privacy push.

Responding to the multi-country intervention, Mr Zuckerberg has acknowledged "really heavy" trade-offs in encrypting communications but defended the company's plans. He invoked the safety of political dissidents and journalists as a key reason for strengthened protections.

Facebook, which owns Messenger, WhatsApp and Instagram, announced in March it would introduce end-to-end encryption across all its services, preventing data from being accessed by people other than the sender and recipient. The company has 2.4 billion monthly users across its core platforms.

In a statement on Friday, Mr Dutton acknowledged encryption was important for security in banking and other services but said "paedophiles are using it to order children and send images of children being raped".

He said Facebook and other companies must have "zero tolerance" for child exploitation and not allow it to thrive on their platforms.

"At the moment, even with a court-ordered warrant police can't access the messages to use as evidence to prosecute these evil criminals. You're either on the side of vulnerable children or not. It is time for Facebook to pick a side," Mr Dutton said.

The joint letter warned Facebook against hampering investigations into serious crimes and called on the company not to introduce the changes without first ensuring law enforcement agencies were able to lawfully bypass the encryption.

"Security enhancements to the virtual world should not make us more vulnerable in the physical world," the letter states.

Following its release, Mr Zuckerberg said prevention of child exploitation had weighed "most heavily" on him in the encryption decision. He acknowledged the change would mean fighting the material with a "hand tied behind your back" but said there was a range of other tools available the company was investing heavily in.

"I still think that the equities are generally in favour of moving towards end-to-end encryption," he told a gathering of Facebook staff that was live streamed.

"End-to-end encryption keeps people safe in other ways. Journalists who are operating in countries where there isn't freedom of the press. Think about things like the protests that are going on in Hong Kong right now."

He said protecting people's communications against undue intrusion by governments was a "valuable thing that we should be proud of trying to deliver".

"I hear stories form dissidents and activists all the time who say that they would be in jail or maybe killed if they couldn't rely on end-to-end encryption. So these are some of the hardest decisions that I think we have to make, is trading off these equities that are really heavy."

Facebook and other tech companies strongly oppose efforts to introduce "back doors" and other vulnerabilities they say will fundamentally undermine the security of their platforms and harm customers' trust in those services.

Australia's eSafety commissioner, Julie Inman Grant, said there could be no "absolutism" on privacy, security and safety on these platforms.

"I view these as three legs of the same stool and if one of those legs is not balanced then the stool will surely fall over," she said.

Ms Inman Grant said the companies needed to take responsibility for mitigating the "horrendous potential damage" of universal encryption.

The tech sector and privacy advocates continue to lobby against Australian legislation that has granted security agencies greater powers to access the encrypted data of criminal suspects.