Otago's annual drowning toll tripled to six in 2013.
Two people drowned in the region in 2012.
Nationwide, there were 81 drownings last year, the lowest number since records began in 1980.
Otago was one of five regions in which the drowning toll rose, and it had the greatest percentage increase. Others were Hawkes Bay, Marlborough, Northland and Bay of Plenty.
Water Safety New Zealand chief executive Matt Claridge said of the six people who drowned in Otago last year, five were men and four were 55 years or older.
They were recreational water users, and he urged Otago's adult male residents to be responsible for their safety and that of their friends while on and around water.
Historically, most drownings in Otago involved adult European males participating in recreational activities.
For every drowning in New Zealand, there were another 1.8 people on average admitted to hospital due to water submersion or water inhalation.
In 2012, there were 11 such cases in Otago.
The corresponding figure for 2013 was not yet available.
Mr Claridge said Otago's annual drowning toll had not been as high for ''quite some time'' although the region's five-year average drowning toll was 7.
All South Island regions had fewer drownings in 2013 than their five-year averages, which in Southland was 5, Tasman 3, West Coast 4 and Canterbury 11.
Although the national toll was down from 98 in 2012 and at a record low, Mr Claridge said 81 drownings was 81 too many.
''Overall, it's great that the toll is tracking down, but 81 deaths is still a huge number, ranking us among the worst in the developed world.''
He said swim to survive programmes must continue to engage children from a young age if there was to be a cultural change in behaviour around water.
Five pre-schoolers drowned last year, up 67% on 2012, and six children aged between 5 and 14 years drowned - double the five-year average of 3 and equal to the 2012 number.
''No pre-schoolers should be drowning in this country. Kids under 5 should be within arm's reach of a parent or caregiver at all times in, on and around water,'' Mr Claridge said.
Nationwide, 77% of all people who drowned last year were men. Sixteen drowned while swimming and another four while participating in other water sports.
Eight people drowned while fishing from land and another eight drowned in incidents involving powered boats.
The greatest number of drownings occurred at beaches (19), rivers (18) and offshore (11).
As of yesterday, there had been four water deaths in New Zealand so far this year.
2013 drownings
Auckland ... 16
Bay of Plenty ... 8
Canterbury ... 3
Gisbourne ... 0
Hawkes Bay ... 6
Manawatu/Wanganui ... 3
Marlborough ... 5
Northland ... 11
Otago ... 6
Southland ... 3
Taranaki ... 2
Waikato ... 9
Wellington ... 5
West Coast ... 4
Total ... 81
