Terangi "Toots" Woonton, 59, and Kairangi Samuela, 53, lost their lives when the 5m boat they were in was swamped while crossing the Manukau Bar in Auckland on December 29.
Auckland student Heng Li, 25, drowned while setting crab pots at Uretiti Beach in Northland on Christmas Day.
Two others drowned while swimming, Jarod Lineses, 16, was swept out to sea at Northland's Ninety Mile Beach on December 27. His body was found on New Year's Day.
Kris Wichman, 36, drowned in the Patea River near Taranaki on New Year's Day, after rescuing his niece and two daughters from the water.
Wayne August, 42, also drowned on New Year's Day after he walked into the sea at New Brighton beach in Christchurch. Witnesses said he appeared to be intoxicated.
Simon Camp, 47, also died on the water this holiday season, while surfing at Karioitahi Beach, 70km southwest of Auckland, on a board he reportedly got for Christmas.
Mr Camp's death was not included in the official holiday drowning toll as the cause of his death was unknown, Water Safety New Zealand said.
Water Safety New Zealand chief executive Matt Claridge said it was a huge disappointment that the drowning toll was so high.
"Anything other than zero would have been a disappointing result but for the number of drownings to be more than last year's festive period - and to include a preschooler - is gut-wrenching."
He said the year was off to a tragic start with two of the seven deaths so far occurring in 2015.
"Two families are already without a loved one and we're less than a week into the New Year."
Mr Claridge said the warm weather was likely a factor in the increase, and it reinforced the need for everyone to think about water safety.
"Summer still has a long way to go so when you're preparing for your day out at the beach, lake or river, take a moment to consider how you'll keep yourself - and friends and family - safe."
Those who died on the water this holiday season:
December 25 - Heng Li, 25, a student, died at Uretiti Beach in Northland while setting crab pots, and Imogen Saleupolu-Mataafi, 1, drowned in a temporary pool set up in the backyard of her family's Manurewa home.
December 26 - Simon Camp, 47, died at Karioitahi Beach, 70km southwest of Auckland, while surfing on a board he got for Christmas.
December 27 - Jarod Lineses, 16, was swept out to sea on Ninety Mile Beach at Hukatere in the Far North. His body was found on New Year's Day.
December 29 - Terangi "Toots" Woonton, 59, and Kairangi Samuela, 53, died when their 5m vessel was swamped by a wave while crossing the treacherous Manukau Bar.
January 1 - Kris Wichman, 36, drowned in the Patea River near Taranaki on New Year's Day, after rescuing his niece and two daughters from the water.
January 1 - Wayne August, 42, was seen by beachgoers walking into the surf at New Brighton beach in Christchurch wearing long pants and a T-shirt on New Year's Day. Witnesses said he appeared to be drunk.
