The number of people who drowned in Otago and Southland last year was double that of the previous year.
Water Safety New Zealand statistics show 13 people across the South drowned in 2019. Six drowned in 2018.
There were also more drowning deaths nationally, increasing from 68 in 2018 to 82 last year.
Water Safety chief executive Jonty Mills said the possible impact of the Covid-19 pandemic on water safety was being considered, following a "significant" increase in drownings while fishing from land and while underwater diving.
Russell McDonald (67), of Waitaki Bridge, was one of the seven people who drowned in Otago last year.
His body was discovered near Black Point in October after a jet-boat he had been fishing on with two others overturned.
In December, another man died after being swept into the water by a rogue wave while fishing at Cape Saunders, on the Otago Peninsula.
The number of drownings in Otago increased from five in 2018, but the number of drowning-related hospitalisations dropped to two last year, compared with six in 2018.
In Southland, six people died from drowning last year, an increase from the one death in 2018, and five people were hospitalised, down from seven the previous year.
Mr Mills said the economic effects of the Covid-19 pandemic and increased unemployment could affect drowning numbers as people sought alternative ways to put food on the table – such as fishing and diving.
"This pressure can result in unnecessary risk-taking and the potential cost is one no family wants to bear.
"It’s so important fishers and divers make wise decisions and follow best practice when it comes to water safety so they come home to their families,” he said.
Nationally, land-based fishing drownings doubled from six in 2018 to 12 people last year.
The 11 underwater diving deaths was also higher, compared with five the previous year.
Overseas studies suggested possible respiratory health issues as a result of Covid-19 could further affect diving drownings, Mr Mills said.
A large increase was also seen in powered boating drownings last year, from two in 2018 to 12 in 2019.
In over a third of those cases, life jackets were either not available or not worn correctly, he said.
"[Life jackets] are no good to you if they are on the boat and not worn when something happens, and an old life jacket, or one that doesn’t fit, will not save your life."
The highest number of drownings last year was among people aged 65 and over, and seven people under 5 years old lost their lives.
Despite the increase in the number of drownings nationally and 203 hospitalisations, the drowning toll was trending down when compared with the country’s growing population.
However, that was too many lives being lost, Mr Mills said.
"Families and communities are left devastated and this has a real and profound impact on many people’s lives.
"While our waterways are our playground, they can be incredibly unforgiving and need to be treated with respect."
Drowning is the leading cause of recreational death and the third-highest cause of accidental death in New Zealand.
