George Brandis has said he regrets his department not forwarding correspondence from terrorist Man Haron Monis on to Australia’s intelligence agency and confirmed no Australians were killed or injured in the Manchester attack.

In an interview on ABC’s AM on Thursday the attorney general cited evidence from the Australian Security Intelligence Organisation and the New South Wales coroner’s report finding that passing Monis’ letter on “would have made no difference” but added that “of course” he regretted that it was not.

On Wednesday the coroner, Michael Barnes, found police should have stormed the Lindt cafe as soon as Man Haron Monis began shooting because in the 10 minutes they delayed, hostage Tori Johnson was forced to kneel on the floor and was murdered by the gunman.

Brandis said the coroner’s report contained “no adverse findings in relation to any of the commonwealth agencies” only “helpful suggestions” the government would study and implement.

While on bail for serious violent offences, Monis wrote to the attorney general asking whether it was legal to contact Islamic State extremists two months before he stormed Sydney’s Lindt cafe. The letter was not passed to Asio.

The NSW Coroner found there “does not appear to be an effective policy in place to require the commonwealth bureaucracy to forward correspondence received by it to Asio where that correspondence is relevant to security considerations”.

Asked about the finding, Brandis said “any deficiency in the Attorney General’s Department’s correspondence handling practice was corrected in 2015” when Monis’s letters came to light.

“I asked my department to initiate a much more rigorous correspondence handling procedure, which they did, so that issue has been dealt with two years ago.”

The procedure is now that any letter raising national security concerns, including “any degree of sympathy or affiliation or interest in a terrorist organisation” will automatically be passed to Asio.

He said his department has helped and will continue to help other departments and agencies to ensure they had security policies in place for sensitive correspondence.

Brandis said military call-out powers were being reviewed and a submission would be taken to cabinet. “Plainly there is an argument, particularly when there is a serious terrorist event to deploy all of the capabilities the nation can summon, whether it be the policing and intelligence capability or the military capability.”

He said in some cases the military would have capabilities the police did not that should be at the disposal of the operational commander.

At a doorstop after the interview, Brandis said before defence powers can be used a “complicated series of steps” must be undertaken and the government was looking to “streamline” those to “make the military more immediately able to be employed”.

Brandis said the military is not usually used for law enforcement and policing but during a terrorist episode “those fine distinctions are less important than getting the best possible outcome”.

He said no Australians were among the dead in the Manchester attack and “so far as we aware there are no Australians among those who are injured”.

On Thursday justice minister, Michael Keenan, told Radio National Australians should be “100% confident our authorities have the ability and wherewithal to deal with [the terrorist] threat”, citing 12 terrorist attacks thwarted in the last two and a half years.

Asked about Tony Abbott’s call for shoot-to-kill powers, Keenan said commanders could already decide to shoot to kill.

He said the NSW police and the Australian federal police both had specialist tactical response teams and the military would not “normally” be used for a siege or terror attack. “If you look at the way terror attacks are working now they begin and end very quickly and the first responders, inevitably, are going to be state and territory police forces and they are equipped to deal with this.”

Keenan said the flexibility to send in the military already existed, but the government would consider changing the mechanics of the call-out powers. “It’s always going to work in a cooperative way, the idea the commonwealth might march in without cooperation of the local police force is ludicrous.”