Rob Mackle submitted his nomination this week to join Hayden Tasker and Dame Lynda Top, with potentially more to come before nominations close at midday on Thursday.
The by-election comes after the death of councillor Rodger Letham in December. With nominations rolling in, there will now be a full election for the vacancy.
All three candidates to be nominated so far unsuccessfully ran in the election in November.
Topp ran third behind deputy mayor Liz McMillan and Letham in the Western Ward.
Tasker, the son of former councillor Bev Tasker and former deputy mayor Roger Tasker, stood for one of the five seats in the Ashburton Ward in October and was the seventh-highest polling candidate.
Mackle, who farms just of Ashburton, stood in the Eastern Ward.
Once the nominations are closed at, eligible voters will have from April 20 to May 12 to cast their votes.
People who did not receive voting papers last October, or who had moved since then, would need to ensure they were on the electoral roll if they want to vote in the by-election.
Voters will be able to return their ballot papers by post or drop them into orange voting bins at the Methven i-Hub, Ashburton Library or council building.
The successful candidate will then be sworn in as a new district councillor for the rest of the term.
Western Ward councillors also sit on the Methven Community Board.
- By Jonathan Leask
Local Democracy reporter
