Government ministers have defended their use of messaging service WhatsApp, despite warnings that it could pose a security risk.
Prime Minister Malcolm Turnbull, his cabinet colleagues and others - including chiefs of staff and media advisers - have been using the Facebook-owned application to communicate instead of other secure platforms.
It's believed the country's cyber intelligence agency, the Australian Signals Directorate, has not approved its use, prompting concerns from experts.
Dan Tehan, the minister assisting the prime minister for cyber security, refused to confirm if that was the case but was confident it was being used properly.
"All I will say is that the government, cabinet ministers, ministers, members of parliament, take their personal security and their security online very seriously," he told reporters in Canberra on Thursday.
He isn't aware of anyone doing anything wrong by using the third-party tool.
"The most important thing is that whatever they do, that they do it in a secure way if they're dealing with material which has a security classification," Mr Tehan said.
Ministers Steve Ciobo and Anne Ruston said they both use the app but not for confidential discussions.
"I don't think there's any security risk associated with using it," Senator Ruston said.
Shadow attorney-general Mark Dreyfus called on Mr Turnbull and his cabinet to stop using WhatsApp immediately.
He suggested the app was being used to avoid any obligations under the Freedom of Information Act.
"They are treating security with contempt," he told ABC radio.
Crossbench senators Nick Xenophon and David Leyonhjelm said they, too, have messaged the prime minister using various apps and have no issue with it.
"What do you want the prime minister to do, use smoke signals? Telepathy?" Senator Xenophon said.
"I think WhatsApp is a reasonable form of communication and safer than others, but I'd like to think the prime minister is smart enough to realise he's not going to be giving any state secrets over anything that isn't sufficiently encrypted."
