Wellington's Matariki fireworks threatened by harbour whale

Wellington's Matariki fireworks display is under threat - from a whale.

The fireworks are scheduled for July 7, and if they go ahead will be the first time in 22 years Wellington's fireworks display coincides with the Māori New Year.

But the event may need to be postponed after a southern right whale was spotted frolicking in the Wellington Harbour. Wellington City Council says its surprise appearance could have a drastic impact on this weekend's display.

The council says it's taking advice from whale experts over the effects the large explosions could have.

"We understand concerns re the timing of #SkyShow18 on Sat while a southern right whale is visiting Wellington harbour," it said on Twitter.

"No decision has been made yet but we are monitoring the situation along with @docgovtnz and will be taking advice from them, we'll keep you updated."

Public sentiment on Twitter has been pro-whale so far.

"Happy to watch the whale not the fireworks," one person commented.