Prime Minister Christopher Luxon picked a "challenging" election date, despite the Electoral Commission favouring two other options, newly released advice shows.
Labour is accusing Luxon of "knowingly limiting turnout" by putting up another barrier to voting.
Advice seen by RNZ shows the commission described the chosen date of November 7 as "challenging, but manageable", partly because advance voting would begin on a public holiday.
Two alternatives - October 17 and November 21 - were considered "administratively more feasible".
In a letter to the prime minister on August 7, 2025, the chief electoral officer warned that school and public holidays could see large numbers of voters away from home, potentially reducing voter turnout.
"Our practice has been to advise on avoiding an election date during these times."
Labour is also concerned there'll be fewer voting booths open on the public holiday.
When Luxon announced the election date in January, he described it as the "logical time", after weighing up sporting fixtures and other events. He noted that eight of the last 12 elections were also held in October or November.
Labour MP Camilla Belich questioned that logic, saying the prime minister had other options that would have avoided the Labour Day clash.
She said just two of the 22 voting places in Epsom, the electorate she is contesting, would be open on October 26 and voters could turn up to cast their ballot, only to find the booth closed.
RNZ suggested to Belich that Labour Day was just one day in a 13-day voting period. She acknowledged the impact might be limited, but argued that even a small number of voters being inconvenienced mattered in a tight election.
"Every vote is going to count," she said. "This is another barrier, really."
Belich said the decision was compounded by the government's earlier changes to electoral law, scrapping same-day voter enrolment.
The National Party has dismissed Labour's criticism as a sign of desperation, pointing out the election date had been public knowledge for nine months.
A party spokesperson suggested Labour leader Chris Hipkins must be "very worried" about his campaign to be raising the matter now.
The Electoral Commission has been approached for more information.
