Heavy rain has forced the cancellation of Auckland's Big Gay Out event.
It is the first time the festival has been cancelled since it began in the 1990s and organisers cited health and safety concerns.
Prime Minister Jacinda Ardern had been scheduled to attend, along with National MPs Nikki Kaye and Chris Bishop.
Big Gay Out is part of the Auckland Pride festival, which runs until next Sunday.
The NZ Aids Foundation is trying to end HIV transmission in New Zealand by 2025 and such events are crucial.
"Events like the BGO are the perfect place to bring a big proportion of the community together and make sure everyone understands how they can play a role in Ending HIV," foundation executive director Jason Myers said.
"We need the LGBTQI community to be as educated as possible on recent breakthroughs, and to foster a sense of community so that we can support each other - especially those living with HIV."