The small insect-eating bird lives only in the forests of New Zealand's South Island and Stewart Island. The birds were relocated by helicopter last week from Breaksea Island off the Fiordland coast to Pomona Island in Lake Manapouri.
Volunteers have spent the past five years clearing the island of pest species such as stoats, rats, mice, possums and deer.
The Department of Conservation initiative aims to establish another viable colony of the threatened bird on a pest-free island.
"The island is an accessible location where locals and visitors will be able to see, hear and learn about native New Zealand flora and fauna, and the establishment of a colony of Mohua will be a major step in that direction," Pomona Island Charitable Trust spokeswoman Viv Shaw said.
South Island robin were also relocated to Pomona Island in 2008.
