For the first time, scientists are taking an in-depth look at what lies below one of the country's most popular lakes.
The mapping of Otago's Lake Wakatipu could provide life-saving information about the lake's natural hazards.
Surrounded by mountains and close to the Alpine Fault, it's thought lake could be particularly vulnerable to landslides or tsunamis.
"You can have tsunamis in lakes, people typically don't think about that but if they experience a really strong earthquake and they're near to the lake shore it's time to move away," NIWA marine geologist Dr Joshu Mountjoy told 1 NEWS.
However, mapping the country's longest lake is no easy task.
Steep cliffs surrounding the lake continue underwater to depths of 300 metres.
NIWA wants to eventually map every lake in the country and hopes to have a better idea of what lies beneath Lake Wakatipu by the end of the year.