A small but growing number of young Muslims are heading overseas and obtaining combat experience that could one day be used against Australia.
At the same time, a navy cadet program in Western Sydney is training young Muslims who may one day fight for Australia.
At Provisional Training Ship Australia in Sydney's west, teenage girls wear black headscarves under their camouflage caps, and boys have full, dark beards.
Until their cadet unit was established in March, neither of those things would have been allowed under Navy cadet rules.
The organisation’s openness to catering for young Muslims is one of the keys to the program's success, cadets say.
"To have the same opportunities without shaving my beard, keeping my religion, it's a big relief,” one teenage cadet said.
Another highlighted the importance of accommodating cadets during Ramadan.
"I think we've all proven to a lot of people that young Australian Muslims can be part of the Australian force."
“I knew that they would take care of needs like halaal food and prayers, and during the month of Ramadan, fasting," he said.
Training Ship Australia was set up in Lidcombe in March as a way to reach out to the area’s multicultural - particularly, Muslim - youth.
The entire Australian Defence Force has just 98 people who identify as being of Islamic faith.
Already Training Ship Australia has nearly half that amount.
Cadets don't always go on to serve in defence, but some are considering it.
One 18-year-old girl said she felt the unit was paving the way for other young Muslims.
"I think we've all proven to a lot of people that young Australian Muslims can be part of the Australian force,” she said.
Most of the cadets at the Training Ship attend Islamic schools and go home to Islamic communities.
Navy Islamic Affairs Advisor Captain Mona Shindy said a recent weekend away with Training Ship Hawkesbury was an eye-opener for all involved.
"They got to experience first-hand a whole bunch of people fasting and they were so wonderful and so flexible in terms of trying to understand and cater for that," Captain Shindy said.
"They got up early with us when we were eating before sunrise. Having dinner at exactly sunset so everyone could eat together."
“I had one girl I sat down with and she said 'I thought it would be different from this.' And I said, 'what do you mean?' and she said, 'they're just like us'."
Professor Greg Barton from Monash University's Global Terrorism Research Centre said programs like this could also help combat isolation and extremism among young Muslims.
“Anything we can do to offer structure, discipline, and purpose and belonging, and affirm people in a positive way will yield benefits,” he said.
Professor Barton said there should be more investment in medium- to long-term outreach programs like this.
"There's no silver bullet here but this is one of the essential elements of what we have to do,” he said.