The European Ombudsman is to investigate allegations that an influential group examining shale gas development is packed with pro-fracking supporters.

The investigation into the European Commission’s Unconventional Carbon Extraction (UCE) group has been launched after it was claimed it is dominated by people with links to the oil and gas industry. According to the EC the group’s efforts are to be the “main source of independent knowledge about fracking and other unconventional oil and gas exploration”.

However critics claim the group, which held its first meetings earlier this year, is heavily weighted in favour of pro-fracking supporters. According to a complaint made to the Ombudsman more than 70 per cent of them either represent or have direct financial links to the fracking industry, two-thirds of the academics and research organisations involved have fracking links and all four chairs and co-chairs of its working groups are fracking proponents.

One of them, Grzegorz PieÅ„kowski, a member of the Polish Geological Institute, said in a recent interview with a gas industry journal that regulators “should not overdo it with these [environmental] concerns and impose new burdens that unnecessarily increase costs”. He said he wanted the group “to demonstrate the absence of environmental risks” which he says are greater in conventional oil and gas extraction.

The complaint says the group “appears to be part of a worrying trend in which EC-advisory groups, usually labelled as Expert Groups, are able to side-step tough rules designed to combat undue influence and conflicts of interest.

Fracking or hydraulic fracturing involves the extraction of shale-gas from the ground using a pressurised liquid made of water, sand, and chemicals. Its supporters say it is safe while its detractors warn it has disastrous consequences for public health and the environment and can even trigger earthquakes.

Environmental fears have led to widespread local opposition to fracking applications. Caudrilla’s application to drill wells near Blackpool, Lancashire were rejected by councillors after strong protests by people who lived in the area.

The Commission insists it is not an advisory group and said the participants reflected the levels of interest they received. The aim of the group was to “bring together practitioners from industry, research, academia and civil society,” a spokeswoman said.

Emily O’Reilly, the European Ombudsman, has previously criticised the EC for permitting systemic industry-domination of expert groups. The Ombudsman has no binding powers to compel the EC to comply with any of her recommendations but the majority are. She has given Commission officials until November to address the complaint, which was made by campaign groups Corporate European Observatory and Friends of the Earth Europe.