It will soon be compulsory to wear lifejackets on all small recreational boats in the Queenstown Lakes District.
The local council has adopted the bylaw after five people drowned in waterways in the region over summer.
Queenstown Lakes District regulatory manager Roger Taylor says the new law will require those on boats smaller than six metres to wear a lifejacket.
The council had to apply to Parliament for a new schedule of infringement fines, with the maximum fine set at $20,000.
The new law will come into effect on 1 June and be enforced by the local harbourmaster.
Wellington Regional Council and other local authorities have already taken a similar line.