Air passengers should face a "significant increase" in taxes, including a new charge for the longest flights, to help combat climate change, a group of MPs said in a report on Wednesday.

The Environmental Audit Committee said higher "green taxes" would cut demand for air travel, help conserve resources and raise money that could be used for environmental projects.

"It is vital that tax on aviation is not just reformed but significantly increased, so as to stabilise demand and resulting emissions," the MPs said.

They said aviation was "very lightly taxed", with a 29 percent cut in real terms between May 1997 and February 2007.

They called for a third passenger tax band to cover "very long haul" destinations, such as Australia. Emissions for a trip to Australia are three times those of a journey to New York, yet both are classified simply as long-haul, their report said.

Taxes on short-haul flights should reflect the fact that high emissions are created during take off and landing, even though the plane may not have a long journey.

Higher taxes on short trips would encourage people to take the train instead, the MPs said.

The committee said it was "puzzled" about why the government had not been bolder in talking about the benefits of green taxes.

"Taxes on high-carbon activities such as driving and flying can be used to reduce their demand without destroying it," the MPs said.