Leading Government scientist Jim Salinger, an international pioneer in climate change research, has been sacked for what he says is talking out of turn to news organisations.

Dr Salinger, 62, says he was summarily dismissed from the National Institute of Water and Atmospheric Research (Niwa) at 4pm on Thursday, and given three and a half hours to clear out his Auckland office.

He told the Weekend Herald he received no formal written warnings leading to his dismissal, which followed a 27-year career as a Government scientist, and no criticism of his work.

Dr Salinger claims the information he provided included calling television weatherman Jim Hickey from Greymouth last week to let him know the rivers were in flood.

His work helped an international group of scientists to which he belongs, the Intergovernmental Panel on Climate Change, share the Nobel Peace Prize in 2007 with former United States Vice-President Al Gore.

Dr Salinger, whose postgraduate studies in 1975 produced what later came to be regarded as a watershed paper on climate change at a time when the concept was resisted by most scientists, is also a Companion of the Royal Society and heads the World Commission for Agricultural Meteorology.

His sacking was condemned last night by Green Party co-leader Jeanette Fitzsimons, who feared it would harm New Zealand's reputation in the world science community and would make all Government scientists nervous about their jobs.

"New Zealand is on a slippery slope when trying to provide Kiwis with a greater understanding of our climate is a sackable offence," she said.

Greenpeace campaigner Simon Boxer said: "It is a sad day for science and New Zealand's credibility on climate change when one of our top scientists is forced out of his job."

Other than confirming that Dr Salinger no longer worked for it, Niwa would make no comment on what it called a confidential employment matter.

Dr Salinger, who has instructed an employment lawyer to fight his dismissal, said he could not understand why he had been sacked so abruptly.

"It's not as though I was doing bad science," he said.

He said that of three instances cited against him of talking to media organisations without proper approval, two involved Television New Zealand, with which Niwa had a contract under his management to provide weather information.

In one of those cases, he said he gained clearance from Niwa's national communication manager for a reporter to join a snow-line survey flight, only to be told afterwards that he should have sought approval from someone e