People should cut their consumption of meat to help combat climate change, a top United Nations expert told a British Sunday newspaper.

Rajendra Pachauri, chair of the UN Intergovernmental Panel on Climate Change (IPCC), told The Observer that people should start by having one meat-free day per week then cut back further.

The 68-year-old Indian economist, who is a vegetarian, said diet change was important in reducing greenhouse gas emissions and environmental problems associated with rearing cattle and other animals.

"Give up meat for one day (per week) initially, and decrease it from there," he said.

"In terms of immediacy of action and the feasibility of bringing about reductions in a short period of time, it clearly is the most attractive opportunity."

Other small-scale lifestyle changes would also help to combat climate change, he said without elaborating.

"That's what I want to emphasise: we really have to bring about reductions in every sector of the economy."

Pachauri is due to give a speech in London on Monday under the title: "Global Warning: the impact of meat production and consumption on climate change".

Pachauri, who was re-elected for a second term six-year term as IPCC chairman last week, has headed the organisation since 2002 and oversaw its seminal assessment report in 2007 which gave graphic forecasts of the risks posed by global warming.

The IPCC warned then that without action the planet's rising temperatures could unleash potentially catastrophic change to earth's climate system, leading to hunger, drought, storms and massive species loss.

The organisation also won the Nobel Peace Prize in 2007 along with former US vice president Al Gore.