Serious crime will no longer be able to hide behind messaging apps or in the cloud under an electronic data treaty between Australia and the United States.
Giving evidence at the parliamentary inquiry into the Australia-US Cloud Act Agreement, senior official Andrew Warnes said the change would enable more cases to get to court.
As it stands, only the "absolute top, top end" most serious cases were going ahead, Mr Warnes from the Attorney General's Department said on Wednesday.
The agreement will give intelligence and law enforcement officers rapid access to US-hosted data to fight terrorism, child exploitation and human trafficking, ending delays of more than a year in seeking evidence.
The treaty must be reviewed by the Australian parliament and the US Congress before it enters into force, which is expected by the end of 2022.
Australia was the second country after the United Kingdom to sign an agreement with the US to access data.
"I don't think we can understate the positive impact that we're expecting this to have on criminal investigations," Mr Warnes said.
The Department of Home Affairs received a stern rebuke for not showing up to answer questions about orders it would be responsible for carrying out.
Committee chair Josh Wilson said being told by an agency they had decided not to appear and would respond in writing was "not acceptable" and a "disappointment".
Mr Warnes made excuses for the team he used to lead at Home Affairs, which Mr Wilson rejected.
"Someone responsible for ASIO needs to be here," Mr Wilson said.
Permission would be needed from the Australian government if evidence was to be used in a case that resulted in the death penalty, and Australian agencies cannot target a US citizen, the committee was told.
Critics also remain concerned about data protection and the reach of US intelligence agencies into Australia.
But Mr Warnes said "very few" requests were expected from the United States, and all work must be justified.
"There's multiple checks and balances in this agreement," he said.
Orders for data must be specific and tied to the prevention, detection, investigation or prosecution of serious crime.
"It can't be a bulk-data fishing exercise, that is not at all what is contemplated," he said.
He said there must be a target person or target account, whether it's Google, Facebook, Apple or messaging apps.
Other federal parliamentary inquiries have been postponed as Australia marks the death of Queen Elizabeth II.