Scott Morrison has accused Bill Shorten of being "happy" for terrorists to plot attacks using encrypted messages as a political brawl over national security legislation continues.
The federal government wants to pass laws designed to give security and police agencies powers to access encrypted communications on applications like WhatsApp.
But Labor is resisting pressure to pass the legislation.
"Labor are quite happy for terrorists and organised criminals to chat on WhatsApp, leaving our security agencies in the dark," Mr Morrison told The Australian on Monday.
"There is no excuse for this type of weakness."
The coalition wants its decryption legislation to clear parliament this week, before the long summer break.
"Christmas is a heightened security issue for us and we need to make sure people are as safe and as secure as possible," Assistant Home Affairs Minister Linda Reynolds said on Sunday.
"It is the lives of Australians at risk, because the threat is real."
A bipartisan intelligence and security committee looking into the bill failed to reach an agreement on a way forward - the first impasse of its kind in more than a decade.
Labor has sided with technology giants and industry groups who fear the legislation, as drafted, could expose Australia to hacking and security breaches.
Cabinet minister Mathias Cormann has accused Labor of siding with terrorists.
"To think that Labor would want terrorists to be able to communicate with each other beyond the reach (of law enforcement) ... I think that Labor are using excuses."
Senior Labor Senator Penny Wong said the coalition was seeking to create a fight over the encryption laws to distract from the government's problems.
The bill in its current form would make Australia less safe, she said.
Labor has offered to pass an interim bill by Thursday to give intelligence agencies temporary powers to better monitor terrorists.
The Law Council of Australia supports aspects of the bill but said it was far too complex to be rammed through parliament in just four days.
"The parliament must proceed with caution to ensure we get it right. Rushed law can make bad law," president-elect Arthur Moses told AAP.
Mr Moses also took a swipe at coalition government ministers for accusing people of putting national security at risk by raising concerns about the bill.
"Allegations like that should not be thrown around like confetti in a democracy such as ours. The energy would be better spent on getting the legislation right," he said.
