Special forces soldiers will provide training to state and territory police forces, and some may be embedded to improve co-operation, under new powers to improve responses to threat of terrorism.
The prime minister made the announcement highlighting the need to constantly review and update national security policy to make sure the government does not ‘set and forget’.
"Our enemies are agile and innovative. We have to stay ahead of them," Malcolm Turnbull said.
Under the changes, it will be easier for Australia's military to help police respond to terror threats. However, state and territory police "are and will remain" primary responders to any terrorist attack.
"It is most likely that a terrorist attack will use simple methodologies, a knife, a gun, a vehicle and the attack itself could be over in minutes," Mr Turnbull said.
As well as specialised training, the government will make it easier for Defence to embed officers within state and territory law enforcement agencies to “assist with liaison and engagement”.
Mr Turnbull said it is vitally important agencies are closely linked with the closest possible collaboration.
"We will be placing Australian Defence Force liaison officers with the counter-terrorism groups, both at the state and territory level," he said.
The changes will mean the Defence Act will be amended to allow states and territories to “call out” the ADF in the event of a terrorist incident.
"We want to make sure every asset we have that is designed to keep Australians safe is brought to bear to do so when it is needed," Mr Turnbull said.
The changes follow a review into the deadly 2014 Lindt Cafe siege.
Justice Minister Michael Keenan says the changes build on an already strong relationship between the military and police.
"In 2005 we never imagined Australia would be under the current terrorism threat that it is," he told ABC radio.
"There would only be limited circumstances in which the niche military capabilities that we have would be required," Mr Keenan said.