Labor candidate Mike Kelly has resigned from the Australian Army Reserves after being asked to stop using images of his uniform in election campaign material.

Dr Kelly said the Australian Defence Force (ADF) asked him on Thursday night not to use his uniform in his election advertisements.

His resignation came a day after WA Liberal MP Andrew Hastie was fired from the Army Reserves for refusing to take down material that featured him in uniform.

Dr Kelly, the former member for Eden-Monaro who is campaigning to reclaim the seat from Liberal MP Peter Hendy, said the request came as a surprise.

"This is my fourth campaign and my interpretation of the defence policy led me to believe that the way I was using material was correct in that I'd always used a sole photo of myself with no other ADF members — only in the context of low-key, biographical, printed material," he said.

Andrew Hastie campaigning in the Canning by-election in September 2015. ( ABC News: Andrew O'Connor )

Labor's candidate for Brisbane, Pat O'Neill, has however complied with a request take down billboards depicting him in uniform.

Three billboards funded by the ALP went up in Brisbane in March.

The ADF contacted Mr O'Neill and asked him to remove them because they had not endorsed them.

Mr O'Neill said although he believed it was important for people to be aware of his history as an Army officer, he has decided to remove them.

Policy designed to keep ADF apolitical

In a statement about Mr Hastie's sacking, a Defence spokesperson said the ADF's policy was designed to ensure it remained apolitical.

"As a condition of their service, regular and reserve members of the Australian Defence Force are obliged to comply with various Defence instructions and policies," the spokesperson said.

"ADF members are therefore not permitted to participate in any political activity in uniform, unless they are pre-approved to do so by an appropriate authority.

"Defence contacted Mr Hastie, a member of the standby Army Reserve, and requested he remove imagery of himself in uniform from election campaign material. Regrettably, Mr Hastie did not comply with this request.

"Accordingly, the Army issued Mr Hastie with a notice indicating the intention to terminate his service because he had failed to comply with directions and Defence policy. Mr Hastie's service has since been terminated."