Malcolm Turnbull insists there's nothing underhand about giving intelligence agencies greater powers to target terrorists' phones.
Instead he says it's about extending the rule of law to "dark places" online.
The government plans to introduce draft laws to force international technology companies to unlock the encrypted messages of terrorists.
The legislation will also give intelligence agencies stronger powers to remotely conduct surveillance on the phones of jihadis and child abusers.
The prime minister's push follows the G20 summit in Germany where Australia led the way on discussions about encrypted technology.
An ability exists now to obtain information from telcos, but not internet companies such as Facebook or WhatsApp.
"We cannot allow the internet to be used as a place for terrorists and child molesters and people who peddle child pornography and drug traffickers to hide in the dark," Mr Turnbull told the Seven Network on Friday.
"Those dark places online must be illuminated by the law."
Mr Turnbull insists he's not giving intelligence agencies "back doors or anything underhand".
Cabinet minister Christopher Pyne is not expecting a fight from the tech giants.
"I think if (companies) do try and fight the government trying to protect Australians they'll be on the wrong side of the argument," he told the Nine Network.
© AAP 2017 Photo credit: AAP Image/Dave Hunt