Western Australian fast food franchises could be forced to list dietary information on their menus after the state government threw its support behind the proposed initiative on Sunday.

The policy of "mandatory kilojoule labeling" is already employed in New South Wales, the ACT, South Australia, Queensland and Victoria and at some venues in Western Australia, but the state has yet to fully commit to the practice.

Some fast food franchises already employ the practice in WA. Credit:Andrew Quilty AQU

WA Health Minister Roger Cook announced his intentions to commit to the policy, and said the Department of Health would investigate its feasibility.