Home Affairs Minister Peter Dutton says Facebook needs to "pick a side" in the battle against online child sexual abuse material, joining his American and British counterparts in ramping up pressure on the social media giant over its plans to roll out encryption across its messaging services.

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.

Facebook CEO Mark Zuckerberg has acknowledged "really heavy" trade-offs in encrypting communications but defended the company's plans. Credit:AP

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.