The extent of powers allowing police to spy on and seize online accounts is being challenged but intelligence agencies argue they're necessary to combat crime.
Australian Federal Police and Australian Criminal Intelligence Commission electronic surveillance and disruption powers are being reviewed by Independent National Security Legislation Monitor Jake Blight.
It spans three warrants allowing the agencies to disrupt, alter or delete data to foil crimes, to tap into electronic servers and computers to get intelligence on criminal networks and to take over digital accounts to gather evidence.
The use of the powers "has not been extensive" and helped tackle scams, fraud, drug importation, child exploitation material and terrorism, AFP deputy commissioner Ian McCartney told an inquiry into the legislation on Thursday.
Data disruption was a valuable tool that helped frustrate the orchestration of serious offences, "particularly if there are limited opportunities to identify, arrest or prosecute those offenders," the head of the crime section said.
Up to 2023/24, there were three applications for data disruption warrants and three issued, 11 applications for account takeover warrants with 12 issued and four applications for electronic surveillance warrants with four issued.
The powers help stop fraud and scams by allowing officers to disrupt threats to tens of thousands of phones or computers, including by shutting down malware, police said.
Police needed powers to investigate and prevent crimes but excessive surveillance and zealous collection of data "can infringe civil liberties and rights and freedoms that we hold dear", Mr Blight said.
The laws "have given authorities unprecedented and invasive powers to hack, surveil and even take over online accounts with very little oversight", Human Rights Law Centre associate legal director Kieran Pender said.
The AFP defended oversight, saying a detailed level of information about why a warrant was needed and other measures wouldn't suffice were outlined in the application.
The ACIC could be stripped of its power to obtain a data disruption warrant, with Mr Blight questioning why it needed it because it wasn't a law enforcement action agency.
Success was measured against the value of the intelligence gathered and the warrants helped discover and track criminal networks, ACIC contended.
"Intelligence, by its nature, is a discovery exercise ... collecting more dots so that we can join the dots to make sense of our environment and identify harmful activity," CEO Heather Cook told the inquiry.
Warrants cover offences with a three-year prison penalty but some want this increased to five or seven years.
A seven-year threshold captured an enormous amount of offences with three-year maximums including child abuse, drugs and money laundering, the Law Council of Australia's Tim Game said.
Police haven't used the powers below the five-year threshold as they target more serious crimes, Mr McCartney said.
Protecting journalists and their sources were also points of contention over the secret warrants and surveillance but Mr McCartney said no journalists had been targeted.
Traditional warrants, such as search ones, meant people were aware of what was happening and could challenge its legality in court but "that kind of challenge just isn't going to happen for covert powers," Mr Blight said.
