In the wake of the horrific Bourke Street attack in Melbourne, the Federal Government has ramped up its push to build public and parliamentary support for its encryption access bill.

“Where you have someone who is buying chemicals, importing or purchasing online different items that might be precursors to make up an explosive device, you would expect there to be intelligence around that activity,” Home Affairs Minister Peter Dutton said.

“Where you have someone who picks up a kitchen knife and grabs a couple of gas bottles and drives into the CBD, these are very difficult circumstances to stop.”

Very difficult. In fact, it makes sense to pause and think about precisely what kind of omnipresent observation would be necessary to stop the possibility of all such random attacks.

The government’s proposed laws are currently being considered by the Parliamentary Joint Committee on Intelligence and Security, which I have addressed on behalf of the Law Council.

The Bill would significantly expand the powers of law enforcement agencies, the Australian Security Intelligence Organisation, the Australian Signals Directorate, and the Australian Secret Intelligence Service.

It would make it easier for these agencies to get access to messages that are sent over encrypted messaging software by compelling designated communications providers to assist them in decrypting user information.

Obviously, there is significant value to public safety in allowing law enforcement faster access to encrypted information where there are threats to national security, or to prevent the commission of serious criminal offences.

The problem is one of proportionality.

The Bill proposed would authorise the exercise of intrusive covert powers with the potential to significantly limit an individual’s right to privacy, freedom of expression and liberty.

And while it would do this in a variety of ways, one of the most serious is how it could sidestep the need for a warrant.

Search warrants, as anyone who has watched a police drama would know, provide police with the right to enter a person’s premises for the purpose of investigating criminal matters.

Generally, police do not have the power to search a person or premises without a search warrant, unless specified circumstances exist which permit police to conduct a search without a warrant.

Currently, police can have a search warrant issued to give them the power to access your computer.

But under the proposed Bill, law enforcement agencies and ASIO could make ‘technical assistance requests’ or ‘voluntary assistance requests’ on designated communications providers.

Under these requests, there is uncertainty about whether a designated communications provider may be asked to undertake telecommunications interception for which authorities would otherwise require a warrant.

Now, it’s hard to imagine an internet provider refusing a written ‘request’ from law enforcement. Which means, in essence, law enforcement and intelligence agencies would have the ability to step around the need to secure authorisation from a judge or the Minister.

This is a major worry. It is a long-standing and central tenet of our system of justice that police should not just be able to rifle through your private messages on a whim.

And while the Law Council is troubled about the potential to circumvent the need for warrants, we are also concerned about the significant expansion of powers in computer access warrants themselves.

Under the proposed Bill, computer access warrant powers will be expanded to allow the use of force against persons or things to engage in telecommunications interception – an expansion the Law Council does not support. The Law Council has also recommended that the expansion in computer access warrant powers be amended so that access to third party premises is limited to cases where an eligible Judge or nominated Administrative Appeals Tribunal member considers it is necessary to execute the warrant.

The Bill also contains proposed new powers that may enable law enforcement or ASIO to require people to provide compulsory assistance.

But if a person is compelled to attend a place to provide information or assistance – and threatened with arrest on suspicion of an offence if they attempt to leave – this starts to look a lot like detention. And when the state detains someone, that needs to be carefully considered and any possible application should trigger a whole host of safeguards.

If the government wants to dramatically extend the oversight of our private lives then the onus lies on legislators to justify it.

Detained people should be allowed to contact a lawyer where client confidentiality is preserved.

In addition, those who provide compulsory assistance should be brought before a Federal Court Judge for a hearing in camera after four hours have elapsed. This would enable an application for release or extension of time period, which is what happens to suspects who are arrested and interviewed under the Crimes Act.

In examining this legislation closely, the Law Council was also concerned to note there is no obligation on decision-makers issuing requests or notices to communications providers to consider whether the perceived law enforcement or national security objective outweighs an affected individual’s reasonable expectations of confidentiality and privacy.

This could easily be improved through the inclusion of a ‘reasonable and proportionate’ test which includes requirements for the decision-maker to consider the reasonable commercial interests of the person to whom the notice relates and the fundamental right to privacy of affected individuals.

This legislation also appears to allow a senior bureaucrat of ASIO to confer civil and criminal immunities for those who provide assistance to law enforcement or security agencies. This is a serious expansion of responsibility, and we think it is better for that power to reside with the Attorney-General, who is more accountable.

Obviously, the idea of a knife-wielding murderer, driven by a deluded ideology, strikes fear into all of us. It’s so chaotic and random that everyone can picture themselves as the victim. So it is natural that we want police to be doing everything possible to protect us.

But the problem with broad-ranging legislation like the Telecommunications and Other Legislation Amendment (Assistance and Access) Bill is it does not limit itself to these efforts.

If the government wants to dramatically extend the oversight of our private lives then the onus lies on legislators to justify it.

In this case, the proposed expansion of police and intelligence agency powers does not seem proportionate to the threat we face.

Morry Bailes is the managing partner at Tindall Gask Bentley Lawyers, president of the Law Council of Australia and is a past president of the Law Society of SA. The opinions expressed in this column are his own.