The selection process is long. First, candidates put their names forward to Labour's head office in Wellington. The office checks they meet criteria, such as good character and membership of the party.
Next the local LEC will hold meetings in Whanganui and South Taranaki to introduce the candidates to party members. Then, possibly in mid-November, head office will get involved in a more formal selection process.
There's a final meeting where both local and head office representatives vote on the best candidate - but neither can veto each other and the decision isn't made on numbers alone.
"It's very much reaching an agreement for everybody," Dempsey said.
"It could come down to votes, but that would be a pretty unsatisfactory way to select a candidate."
The New Zealand Labour Party will hold its 2019 conference in Whanganui in late November and early December. About 800 delegates are expected.