Australia's biggest military exercise this year has been called off due to the coronavirus crisis.

Key points: Exercise Hamel had been planned for August and was meant to have thousands of troops certified ready for overseas deployment

Exercise Hamel had been planned for August and was meant to have thousands of troops certified ready for overseas deployment The Defence Force says it must focus on the most prevalent threat to the country, which at the moment is coronavirus

The Defence Force says it must focus on the most prevalent threat to the country, which at the moment is coronavirus Military personnel are being deployed to assist in the Government's COVID-19 response, including helping police with border control measures

The biennial Exercise Hamel is used to test soldiers' combat skills over several weeks of realistic fighting scenarios.

About 8,000 troops were due to descend on Townsville for the war games in August.

Townsville's 3rd Brigade was due to complete the exercise to be certified ready ahead of deployment overseas next year.

The combat brigade's commander, Brigadier Kahlil Fegan, said Hamel might not happen until 2021 or the year after.

Brigadier Kahlil Fegan, Commander of 3rd Brigade says training programs are not a priority at the moment. ( ABC North Qld: Siobhan Heanue )

Stay up-to-date on the coronavirus outbreak Download the ABC News app and subscribe to our range of news alerts for the latest on how the pandemic is impacting the world

'Most prevalent threat'

"Hamel and that high-end collective warfighting environment and training outcomes are just not the priority for us at the moment," he said.

"We just have to rethink how we certify ourselves for the most prevalent threat, and at the moment the most prevalent threat is coronavirus."

Brigadier Fegan said social distancing restrictions also ruled out participation in international military exercises this year.

Australian troops were due to take part in the world's biggest naval warfare exercise, RIMPAC, in Hawaii in July.

It would have seen 25,000 troops from 25 countries gather for war games.

The international air force exercise Pitch Black, also scheduled for July, in Darwin will go ahead according to the latest information from the Defence Department.

It typically involves 3,000 personnel from 13 countries.

Helicopter involved in the Australian Defence Force's 2018 wargames Exercise Hamel ( Supplied: LSIS Jake Badior, Australian Defence Force )

"In light of the restrictions, we won't be engaging in international activities until the Government decides it's safe for us to do so," Brigadier Fegan said.

Operation COVID-19 Assist

The virus has forced the Army to rapidly change the way it does business, with between 30 and 60 per cent of soldiers from 3rd Brigade now working from home instead of on base at Lavarack Barracks in Townsville.

The brigade is among the resources that can be called upon to help governments respond to the coronavirus crisis as part of Operation COVID-19 Assist.

More than 1,000 Defence Force personnel have been mobilised around the country.

They are helping with work such as contact tracing, protecting remote communities and helping police staff border controls and check people in mandatory isolation.

The largest contingent of more than 500 personnel is working in New South Wales.

Working with police

Up to 200 soldiers from 3rd Brigade are assisting police in western Queensland, mostly with border control measures.

Brigadier Fegan said he had to cut short a training exercise for soldiers and medics when the ADF stepped up its response to the pandemic.

"I started pulling all my assets off the hill, and that was a few thousand soldiers," he said.

Instead of training in Exercise Hamel, soldiers will be working in Operation COVID-19 Assist. ( Supplied: LSIS Jake Badior, Australian Defence Force )

He said soldiers were now training to better understand the coronavirus threat while waiting for further requests for help from the Government.

"One of the greatest risks soldiers face is complacency, when we let our guards down.

"As soon as we do that, much like a cancer it can creep into our lives and potentially kill us.

"I've been emphasising to the soldiers that now is not the time for ourselves or our families or our communities to become complacent."