Former veterans affairs minister Darren Chester has confirmed he will challenge Barnaby Joyce for the Nationals leadership when the party meets in Canberra.

“We need to be honest with each other in the party room and take some responsibility for the Liberal losses in the city,” Mr Chester told The Sydney Morning Herald and The Age late on Thursday.

“How we develop our policies, deliver our message, and work with our Coalition partners in the future will determine whether we can return to government and deliver for regional communities.”

Nationals MP Anne Webster has publicly declared her bid for the deputy leadership.

Mr Chester and Dr Webster’s declarations came ahead of the Nationals’ meeting in Canberra on Monday to spill the positions of leader, held by Mr Joyce, and David Littleproud’s deputy role.

Former leader Michael McCormack and Mr Littleproud are also understood to be interested in the top job.

Mr Joyce has said he would nominate even if there was a challenge, noting his party had held all of its seats at the poll.

The Nationals automatically spill the leadership after an election.