The Federal Government is set to introduce new laws that will enable law enforcement and intelligence agencies to access encrypted messages from social media companies.

The new laws would force tech-giants such as Facebook, Google, WhatsApp and Signal to hand over and decrypt messages of suspected terrorists and criminals to law enforcement agencies.

Prime Minister Malcolm Turnbull believes the legislative changes are a way to prevent criminals from using the internet as a place to “hide in the dark.”

Speaking at a press conference at the Australian Federal Police (AFP) headquarters in Sydney, Turnbull said the planned laws would modernise existing legal principles.

"We need to ensure that the internet is not used as a dark place for bad people to hide their criminal activities from the law, and the AFP must have the powers to enforce the law online as well as offline," Turnbull said.

"Increasingly, communications across the net, whether it's messaging or voice applications, are encrypted end-to-end. So, while they can be intercepted, they cannot be read.

"We want to ensure the brilliant tech companies bring their brilliance to assist the rule of law. Not through 'back doors', but through legitimate ways so they can keep us safe," he said.

Attorney-General, George Brandis, echoed the Prime Minister, saying, “the existing law was written before the advent of social media, before the growth in very recent years of encryption of communications to a point at which it is now effectively ubiquitous.”

“So, in order to address the new technological developments, we are contemporising existing, well-established legal principles.”

The proposed laws would work by asking tech companies to provide moral-based assistance to allow law enforcement agencies to access encrypted information, rather than creating deliberate weaknesses or ‘backdoors’.

Acting Commissioner for the AFP, Michael Phelan, welcomed these reforms on behalf of all law enforcement and intelligence agencies.

“Sixty-five per cent of our serious and organised crime investigations, counterterrorism investigations, major paedophile investigations, now involve some sort of encryption,” Mr Phelan said.

“At the end of the day, what has happened here is legislation has not yet kept pace with technology.

“What we're advocating here, certainly on behalf of all of us, is no change to what we're able to lawfully intercept, just now giving us the power to be able to see that material.”

However, Facebook has already made it clear they will not assist law enforcement with these proposed changes.

"We appreciate the important work law enforcement does, and we understand their need to carry out investigations,” a Facebook spokesperson said.

“At the same time, weakening encrypted systems for them would mean weakening it for everyone."

Despite this, Opposition Leader, Bill Shorten has come out in support for the planned legislation change.

"We are in this together,” he said on Friday.

"With terrorism a 21st century conflict, we need 21st century weapons to deal with it.

"The big tech giants have a position of privilege in our society, so it is appropriate that they contribute to the safety and well-being of Australian society."

The legislation is due to be brought forward to Parliament in the Spring sittings.