CLIMATE change bureaucrats are now among the most travelled public servants in the land - spending an average of $250,000 a month on overseas conferences and study trips.

As 40 boffins prepare to leave next week for the resort town of Durban in South Africa for the doomed UN climate change conference, The Daily Telegraph can reveal last year's overseas trips cost taxpayers $3.1 million.

According to documents supplied by the department, 86 staff travelled overseas, flying business class or first class during 2010.

The bureaucrats - including assistant secretaries, deputy secretaries, senior executive officers and research scientists - racked up accommodation and meals bills of more than $750,000.

The documents claim a total of more than 250 individual trips or cities were visited during the 2010 calendar year.

Paris, London, New York and Madrid were regulars.

But some lesser known cities included Cartegena, Bogota, Addis Ababa, Cancun and Libreville, the capital of the central west African nation of Gabon.

Reasons for travel included trips to plan for future trips, "energy efficiency discussions", talks with officials and study.

But the travel costs have infuriated some members of the executive government who are urging the Expenditure Review Committee to curb the extravagance of public servants, particularly in Climate Change Minister Greg Combet's department.

"This department is an empire that Darth Vader would be proud of," a source said.

Liberal senator Simon Birmingham, who requested the information, said costs were over the top. "Australians will rightly wonder whether they're being forced to pay higher electricity bills thanks to the carbon tax just to help fund the massive travel costs of the climate change bureaucracy."

Mr Combet's office said all departmental travel is "on official business".

Originally published as Climate change fat cats go global