Internationally renowned conservationist Don Merton died today after a battle with cancer. He was 72.

It was reported earlier this week that Dr Merton had advanced pancreatic cancer and his wife, Margaret, was caring for him at their Tauranga home.

Dr Merton died early today, Forest and Bird executive member Peter Maddison said in a statement this afternoon.

"Forest and Bird is extraordinarily grateful for the work Don did over several decades," Dr Maddison said.

"His legacy is seen in the healthier populations of New Zealand's most endangered native birds today."

He credited Dr Merton with saving the kakapo, the Chatham Island black robin and other native New Zealand birds from extinction.

"He was a guru of the conservation movement."

Dr Merton started working for the Wildlife Service in the late 1950s and was involved in eradicating pests such as rats, who were devastating to native birds, from islands offshore from New Zealand, and in the Indian Ocean.

He began ground-breaking work rescuing the Chatham Island black robin and kakapo from extinction in the 1970s, at which point just five robins remained, including a single successful breeding pair.

Dr Merton used innovative ideas, including cross-fostering with other bird species to save the robin, Dr Maddison said.

Dr Merton was a senior member of the Department of Conservation's threatened species section before he retired in 2005.

He was honoured by several environmental awards and a Queen's Service Medal for services to New Zealand in 1989.

In 1992, Massey University granted him an honorary Doctorate of Science for his contribution to science.

Dr Merton wrote or co-wrote more than 145 publications, including books, articles and scientific papers, to pass on his knowledge and techniques.

He moved to Tauranga with his wife in recent years, where he was active in local conservation issues.