Campaigners reacted angrily on Tuesday to the recommendation by government advisers that "fracking" for shale gas can resume in the UK, despite reassurances that the controversial technique is safe.

In a report published today, experts said fracking could resume with stronger controls after it was halted last year following two earthquakes near Blackpool after the drilling of two sites in Lancashire by Cuadrilla Resources. The "fracking" process, hydraulic fracturing, involves a well being drilled hundreds of metres deep and pumped full of water, sand and chemicals in order to release methane gas.

But green groups and local anti-fracking groups angrily denounced the report. Former Friends of the Earth director Tony Juniper said this morning that it cast "grave doubt" on the government's commitment to cutting greenhouse gas emissions. A study by Cornell University last year predicted its impact on climate change would be worse than coal.

Elsie Walker, an activist from the Frack Off group that has staged protests at Cuadrilla rigs and fracking conferences in London, said: "This report is a seriously dangerous distraction. People need to understand that the wave of unconventional gas development that is threatening the British Isles will bring with it far greater consequences than a number of small earthquakes."

She added: "Even within the narrow context of earthquakes, this report misses all the real issues such as sub-surface damage to wells causing them to leak, the much larger earthquakes seen in the US as a result of wide spread shale gas development and the potential effects on sensitive infrastructure like nuclear power stations and railway lines."

Vanessa Vine, a resident in the Sussex village of Balcombe where Cuadrilla has a licence to frack and a spokeswoman for the No Fracking in Sussex group, told the Guardian: "The British people need to be extremely concerned that our legislators and advisers … have allowed themselves to be so blatantly manipulated by Cuadrilla and the rest of the invading international shale gas industry. It simply beggars belief that they try to mollify us with risible reassurances that the earthquakes - which they acknowledge that they will continue to cause - are not likely to cause any 'significant' damage. Just how credulous do they think the British people are?"

But experts, including one of the report's authors, Brian Baptie of the British Geological Survey, said there was only a "very small" risk of damage from earthquakes caused by fracking.

"Even in a low seismic country like the UK, we get roughly 16 earthquakes [like these ones caused by fracking] in the UK each year … We think the maximum magnitude that might occur could be around magnitude three. That's based on the analogy with coal mining, and there's a long history of coal mining earthquakes over previous decades and the largest of those had a magnitude of three." He added that while earthquakes of that size could cause some minor superficial damage, they would not cause structural damage.

Richard Moorman, chief executive of Tamboran Resources, which has a licence to frack in Northern Ireland, said the process was "perfectly safe if properly regulated."

Simon Moore, a research fellow at the Policy Exchange thinktank, told the Guardian: "The report takes a pragmatic step in allowing us to establish the real potential of shale gas in the UK. At the same time, it is crucial that we have an energy policy framework that is able to take advantage of shale gas's potential, or that of any new technology, without sacrificing important climate goals. This means a credible, longer-term, EU-wide cap on emissions and maintaining Britain's flexible electricity market."

A report earlier this year for Ofgem by management consultants Poyry suggested shale gas from techniques such as fracking was likely to only provide 1-4% of UK gas by 2020. It also said local objections could hamper its uptake. "The unconventional gas reserves could be significant in terms of maintaining indigenous supplies. However, there are a number of issues that might prevent a US-style shale gas revolution from taking place. Not least of those issues is how Nimbyism might generate a lack of public support for onshore drilling activities."

A decision on whether to allow Cuadrilla to continue fracking is due by the government in six weeks' time, with ministers expected to green light it. A spokesman for the Department of Energy and Climate Change said: "No decision has been taken on whether to allow fracking to resume at Cuadrilla's sites in Lancashire. We are grateful to the authors of the report and have launched a call for evidence to give people a chance to express their views on the report. Responses to the call for evidence will be carefully considered before ministers make a final decision."