Police have named the five people who died when a vessel - chartered for a birdwatching trip - overturned in Goose Bay, Kaikōura.
They were Catherine Margaret Haddock, 65 and Susan Jane Cade, 63 of Lower Hutt, Diana Ruby Stewart, 68, Peter Charles Hockley, 76 and Maureen Patricia Pierre, 75 of Christchurch.
The group were members of the Nature Photography Society of New Zealand and had travelled to Kaikōura last weekend for a field trip with the aim of photography the coastal environment and wildlife including birds and seals.
On Saturday morning, 10 members left South Bay on a three-hour trip to photograph birds with charter company Fish Kaikōura aboard the eight-metre boat i-Catcher.
Shortly after 10am, a mayday call was sent out when the boat capsized in Goose Bay, 20 kilometres south of Kaikōura.
A rescue operation saw helicopters, Kaikōura Coastguard and other boats head to the scene to assit.
Six people, including the skipper were rescued from the water, but five died.
Cathye Haddock's husband of 30 years, Peter Simpson said his wife loved the outdoors and had been excited about the photography society field trip.
He said Haddock and spent much of her career working in risk management and outdoor education. She was a long serving Mountain Safety Council volunteer, had chaired the Risk Management Committee and wrote a safety manual on risk management for outdoor leaders after the 2008 Mangetepopo canyoning disaster.
In a Facebook post, MSC said Cathye's impact on outdoor education, outdoor safety and risk management was profound.
Susan Cade has been described by her neighbours as an adventurous spirit who loved gardening and the outdoors.
Former Wellington mayor Celia-Wade Brown is the co-chair of the Wellington Sea Kayak Network group which Cade was a member of and said if there was any small consolation it was the fact that Cade lived life to the full.
"Not only was she doing something that she loved, but she also packed a lot into her life," she said.
Diana Stewart's former workplace, Dental Place NZ in Mount Maunganui, wrote on Facebook that they were "deeply saddened" to hear their former receptionist of many years had died.
"Ever kind and caring, Diana was an expert photographer with a passion for nature, and will be sadly missed by all who knew her."
They said she had been out with friends doing what she loved best.
Peter Hockley was remembered by Otematata Residents' Association chairperson Steve Dalley who became good friends with Hockley, as he had a holiday home in the Otago town.
"He was extremely well thought of locally and it's quite a shock to everybody."
Maureen Pierre was also a keen photographer and longstanding member of the Nature Photography Society.
Skipper Mark Ealam was among six who survived the ordeal and his wife Sharlene said the couple were devastated beyond words.
"What has happened is an unprecedented tragedy," she said.
"And our thoughts and our prayers and our love are with the families of the deceased."
Te Rūnanga o Kaikōura have placed a two-week rāhui from Paia Point north of Goose Bay to Omihi campground in the south, extending out 500 meters from the shore.
Transport Accident Investigation Commission (TAIC), Maritime New Zealand and police are investigating the incident.
Detective Sergeant Michael Whitty said on Saturday it appeared the boat had been in a collision, "with what, we don't know".
There are unconfirmed reports a whale surfaced beneath the boat, causing it to capsize.
Two TAIC investigators have been assigned to secure evidence, talk to witness, examine any electronic evidence available and look at the circumstances of the incident.
The Transport Accident Investigation Commission opens an inquiry when it believes the circumstances of an accident or incident have - or are likely to have - significant implications for transport safety, or when the inquiry may allow the Commission to make findings or recommendations to improve transport safety.
Kaikōura Mayor Craig Mackle said the combined response of emergency services and the many locals who supported them achieved the best outcome that was possible from such a tragic event.
"Our small community is very tight knit and a tragic event such as this is felt by everyone. It makes me really proud to see how we all continue to come together and support each other in times of adversity."
Mackle said he would not speculate on what has happened, but will wait on the outcome of their investigations.