Humpback whales are making a comeback off New Zealand, a survey shows.

The number of humpback whales in the Cook Strait, between the North and South Islands, reached a high in 2015, which the New Zealand Department of Conservation said was an encouraging sign for the local population.

Looking up: Humpback whales. Credit:Kirk Gilmour

In the annual four-week survey, 137 humpback whales, including the rare white humpback Migaloo, were counted. The previous high was 106 in 2012.

Survey leader Nadine Bott said the latest survey results were exhilarating, but also provided encouraging signs for the future.