Home Affairs Minister Peter Dutton has accused tech executives of being "morally bankrupt" on the issue of child sexual exploitation, dismissing Facebook's claims the safety of its users is a top priority as it moves towards encrypting all its messaging services.

Mr Dutton hit out at what he called "public relations spin" in a letter from Facebook executives that declared the company would not abandon plans to roll out end-to-end encryption of all private communications on its platforms, despite the urgings of Western governments.

Home Affairs Minister Peter Dutton called on companies to use their technical nous to mitigate the risk to children. Credit:Alex Ellinghausen

The executives in charge of Facebook's WhatsApp and Messenger platforms wrote to Mr Dutton and his US and British counterparts this week, saying any weakening of encryption would be a "gift" to the world's criminals, hackers and dictators and endanger innocent people.

In a speech to a global summit on online child exploitation on Thursday night, Mr Dutton named Facebook chief executive Mark Zuckerberg and Apple chief executive Tim Cook as among the tech leaders who were "morally bankrupt on the issue of encryption and protecting children".