The fourth candidate, Nanaia Mahuta, was absent due to a prior media engagement.
While he did have a personal opinion on who should be the party's new leader, he would be happy to serve under any of the candidates, Mr McAnulty said.
"A leader that can articulate our policies in a way that demonstrates how they affect Wairarapa - that's the kind of leader that I want, and I can see that in all three leaders that were there."
This was only the second time Labour had held a party-wide vote, and it was important members had a chance to participate, Mr McAnulty said.
"It helps members become engaged - they feel like they have got a stake in the party."
Voting opened on Tuesday and is open to the party's MPs, members and affiliated unions.
Caucus and membership each get 40 per cent of the vote, affiliated unions making up the final 20 per cent of the vote. The party uses a preferential system where voters rank the candidates from best to worst.
Voting closes on November 18 and results are expected to be announced on the same day.