Five people have been killed and six were rescued after an "unprecedented" possible smash between a boat and a whale at sea.
Sergeant Matt Boyce said the families involved were being supported after the incident off the coast of Kaikoura in the south of New Zealand.
It has been reported the boat contained a group of bird enthusiasts aged over 50 and overturned around 10am on Saturday, September 10.
Prime Minister Liz Truss spoke to her New Zealand counterpart and expressed her condolences in a recent phone call.
A Downing Street spokeswoman said: "The Prime Minister spoke to New Zealand Prime Minister Jacinda Ardern this morning, following the death of Her Majesty The Queen. "The leaders spoke about the fondness felt for Her Majesty The Queen, both in the United Kingdom and New Zealand, and shared their condolences.
"The Prime Minister also expressed her sincere condolences for New Zealand after the capsize of a boat off the coast of the South Island in recent hours."
Kaikoura's mayor confirmed the belief the 8.5-meter boat had overturned after colliding with a whale, though they are unable to confirm this.
Craig Mackle said: "We have an upturned boat tipped over by a whale from what we can understand, come up from underneath.
"We've shut the harbour down so that they can carry on working."
An inspector from Maritime New Zealand is coming from the city of Christchurch to investigate what happened.
The five bodies were recovered from inside the stricken boat. The incident occurred in calm seas with no waves, according to local media reports.
Police believe the boat overturned in such a way that a whale may have been the culprit. Authorities had ruled out a log overturning the vessel as it would likely have punched a hole in the hull instead of overturning it.
"This is a tragic event that affects many lives, not least of all families and loved ones. Our heartfelt sorrow and condolences to you all." Mackle added at a press conference.
"I would like to thank everyone involved in the rescue and the recovery. Being able to bring everyone home is the best result in such a terrible circumstance.
Whales are common in the area and a local whale watch company recorded two humpback whales coming unusually close only recently.
Kaikoura Whale Watch said their boats usually stay 50 metres away.
The tourist site for the town says Kaikoura is the "perfect place for marine life encounters" and "whales, fur seals and dolphins live permanently in the coastal waters".
Footage on social media showed the boat had flipped upside down and the surviving passenger perched on top of it.
The town has a population of just over 2,400 and the horror incident has likely left the community shocked.
Local Richard Hill owns Cods and Crays fish and chip shop in the town and said he had worked with the captain of the boat before, who was found to have survived.
Hill told media: "He's a very safe man, there's no way he'd take any risks. So there's just got to be something sort of a freak of nature, I would have thought. A very sad day for Kaikōura really, just a shock."
