''Any death is a tragedy.
''It's something we need to be aware of and just try to do what we can to make sure that we don't have any repeat,'' Mr Black said.
Five people, four of them from Christchurch, have died in four incidents in small boats, mainly jet-boats, since mid-February, three of them in the Fiordland National Park.
The body of a 69-year-old woman was recovered near Teal Bay at New Zealand's deepest lake, Lake Hauroko, in the national park area, last weekend after the latest fatal incident, in which a man and a woman from Christchurch failed to return from a trip in a small fibreglass boat.
Police yesterday temporarily suspended their search for the remaining body because of poor weather conditions, and asked anyone finding boat wreckage to record the location and contact police.
Wairaurahiri Jet operator Johan Groters, who has been helping in the search, believed the vessel was ''too small'' and was not ''suitable'' for the 462m-deep lake.
A well-known farmer from the Te Anau basin, Shane David Gibbons, died on March 18, after a jet-boat crash on the Hollyford River, also in the national park.
On February 24, Christchurch jet-boat competitor Cameron Moore died during the Otago Rivers Jet Boat Race, near Luggate, after the jet-boat left the river and went up a bank.
Daniel McLellan-Skeggs (29), of Christchurch, was swept away after a jet-boat crash on the swollen Taramakau River, on the West Coast, south of Greymouth, on May 17.
Mr Black said there were questions about the suitability of the boat on Lake Hauroko, and, in the case of the West Coast incident, people should avoid travelling in boats in flooded rivers.
''It's a wrong call. It's the human factor,'' he said of the last three deaths.
''It's a matter of educating the human to make things safer.''
Water Safety New Zealand chief executive Jonty Mills said last year had been positive nationally for water safety, including a drop in overall drownings from 92 to 68 and a big drop, from 16 to six, in boating fatalities.
Nevertheless, he was concerned about the recent spike of southern small boat-related deaths and said ''there's no room for complacency''.
Alpine lakes could ''appear to be quite benign but are very, very changeable in terms of weather conditions''.
A key factor was for ''people to make wise decisions. If in doubt, stay out''.
Otago Regional Council harbourmaster Steve Rushbrook paid close attention to all water-related fatalities and ''we certainly are raising our game'' over harbour bylaws and other safety initiatives.
''Over water safety and boating safety, there's never any reason for complacency,'' he said.
Over the next six months people would ''start to see marked improvements'' when it came to new safety signage to guide boat users in the Otago Harbour, Mr Rushbrook said.
Water Safety New Zealand said more than a quarter of drowning deaths were boating related.
