A committee of British lawmakers demanded a national moratorium on fracking due to environmental concerns on Monday, ahead of a crucial vote intended to boost the shale gas industry.

An inquiry by the cross-party Environmental Audit Committee, which examines the effect of government policy on the environment, found the extraction and burning of more fossil fuels was contrary to Britain's pledge to cut greenhouse gas emissions.

It warned that fracking -- in which water, chemicals and sand are pumped at high pressure underground to extract gas -- posed uncertain risks to public health, air quality, and water supplies.

"A moratorium on the extraction of unconventional gas through fracking is needed to avoid both the inconsistency with our climate change obligations and to allow the uncertainty surrounding environmental risks to be fully resolved," the report said.

It comes as lawmakers prepare to vote on the Infrastructure Bill, which contains a number of measures intended to kick-start the fledgling British fracking industry.

Britain has pledged to cut greenhouse emissions by 80 percent by 2050, and several MPs on the committee tabled an amendment to the bill to call for a moratorium.

The report was the latest blow to Cameron's pledge to go "all out" on developing shale gas and oil, which the government says will boost the economy, provide employment and help Britain be less reliant on energy imports.

Last week, a report by Lancaster County Council recommended rejecting plans by British energy firm Cuadrilla to drill at two sites, saying it would have an "adverse affect" on the life of local residents.

The report noted public opposition to fracking, and criticised a provision in the Infrastructure Bill that would make it easier for energy companies to drill beneath homes without residents' permission.

In addition to the moratorium, the committee recommended that fracking be banned outright in protected areas such as national parks, ancient woodlands, and areas that feed groundwater sources.

The report found that an argument in favour of fracking which contends it could be a "transition" fuel used to replace dirtier coal was invalid, as coal would be phased out by the time large-scale extraction was underway.

The Department of Energy and Climate Change rejected the report.

"UK shale development is compatible with our goal to cut greenhouse gas emissions," a spokesman said.

"To meet our challenging climate targets we will need significant quantities of renewables, nuclear and gas in our energy mix. Shale gas has huge potential to create jobs and make us less reliant on imports."