New Australian Defence Force recruits will be needed to remain available for call-up for a decade after leaving service.
The ADF has been looking to lift its full-time and reserve numbers and a 2024 review found it could ask more from those leaving service.
The post-service commitment for new ADF personnel will double from October 1, with existing members able to opt-in.
The ADF has doubled the "commitment period" needed of all personnel from five years to ten, in an effort to grow the pool of people it can call upon in a crisis.
The requirement to remain in Australia's reserve forces has been in place for anyone entering the ADF since 2016.
The longer time frame will automatically apply to recruits from October 1, while existing personnel will be able to opt-in to ten years.
Asked about the change, Defence Minister Richard Marles pointed to recent ADF recruitment figures as a positive sign for the military.
Last week, the ADF announced its permanent headcount had reached more than 64,000 — a 25-year high.
The 2024 Strategic Review of the Australian Defence Force Reserves pointed out the large cost of training full-time military personnel.
The ADF has also been on a years-long campaign to lift its recruitment levels, missing its permanent recruitment target in 2024-25 by 23 per cent.
Jennifer Parker, a former naval officer and adjunct professor at the University of Western Australia, said she does not think the increased service obligations will hinder recruitment.
As of March 2024, the total number of people in the ADF Reserve was 41,717 — including 9,406 people in the unpaid service category two.