Although the number of drownings is lower than last year, the toll is still too high, Water Safety New Zealand says.
Two men died this weekend, one while diving north of Auckland and the other when his boat overturned while he was collecting crayfish pots, north of Napier.
Since January, 31 people have drowned compared to 37 at the same time last year.
Water Safety spokeswoman Wendy Pannett said seven of the victims were aged between 15 and 24, and swimming accounted for the most deaths, with nine.
Of the 31 victims, 29 were men. Auckland University water safety expert Dr Kevin Moran said last month men underestimated risk and overestimated their abilities.
Waikato had the highest toll this year with eight drownings.
Find out more information about New Zealand water safety here.