Wellington's Matariki fireworks display has been postponed until next weekend due to the presence of a southern right whale in the harbour.

Photo: Maritime NZ/Mark Dittmer

Wellington City Council made the announcement this afternoon.

"The advice we've received is that the noise from the fireworks is unlikely to cause harm to the whale but that it could cause it to act unpredictably if it is in the vicinity," acting mayor Jill Day said in a statement.

"We don't want anyone in boats or kayaks on the water, in the dark, to come off second-best if the whale breaches among them.

"Hopefully by next weekend the whale will have departed the inner harbour and headed to Petone or Eastbourne or out into Te Moana-o-Raukawa (Cook Strait)."

Ms Day said there had been strong iwi and public support in favour of postponing the display.

"Wellingtonians have fallen in love with this whale - this taonga - and they've been telling us they don't want anything untoward to happen to it," she said.

"The whale's presence is a true blessing for Matariki."

Locals RNZ spoke to yesterday were firmly in support of postponing the event if the whale was still in the harbour come Saturday.

"I'd rather see whales than fireworks any day of the week," one man said.

"I think they should definitely, even if they're not entirely sure if he's there or not, it'd be much nicer to think he wasn't going to be disturbed," a woman said.

"If they whale is still here I'd cancel it, protecting the wildlife is more important," another man said.