The Church of England is so concerned about a British mining company's position on a national park in Congo that it is threatening to sell its £3 million investments in the company.

The Observer newspaper reports today that the Church is threatening disinvestment if it does not get reassurances from Soco about its operations in Virunga.

Soco's controversial decision to do a seismic survey in the Virunga national park in the Democratic Republic of the Congo was featured in a Netflix documentary backed by Leonardo DiCaprio and shortlisted in this year's Oscars.

The park is home to about half the world's 950 mountain gorillas, but Soco says it does not operate in the mountainous Mikeno section of the park, the volcanoes or the equatorial rainforest, all where the endangered animals live.

The company has been under pressure from the British government, UNESCO and celebrities including Sir Richard Branson to pull out of the park and last year, after it had finished its survey, announced it would do so.

A statement on the documentary's website says: "We are asking Soco to make a written commitment to the Democratic Republic of Congo's government to never again work within Virunga national park's existing borders."

In a statement to the Observer, the Church, which has been talking to Soco for 18 months, said: "Following board-level engagement between the Church of England Ethical Investment Advisory Group (EIAG) and Soco International plc, the EIAG has raised serious concerns about the company's determination to satisfactorily address, in an open and transparent manner, allegations concerning the operations of Soco in and around the Virunga national park in the Democratic Republic of Congo."

Joanna Natasegara, the film's producer, said she was delighted about the impact of the fim. "We always hoped the film would bring the story of Virunga to the fore. We are truly excited that the Church of England has responded in this way."

In a statement published last year with WWF – which has campaigned against mining in Virunga –  Soco said on its website that it had reached an agreement in relation to WWF's complaint to the UK National Contact Point under the Organisation for Economic Co‐operation and Development guidelines for multinational enterprises. On the basis that SOCO agreed to issue and honour the statement set out below, WWF agreed to stop further pursuit of its complaint.

Sock said: "In relation to Virunga National Park we will complete our existing operational programme of work in Virunga which we anticipate will conclude within approximately 30 days of the date of this statement.

"The company commits not to undertake or commission any exploratory or other drilling within Virunga National Park unless UNESCO and the DRC government agree that such activities are not incompatible with its World Heritage status.

"Soco commits not to conduct any operations in any other World Heritage site. The company will seek to ensure that any current or future operations in buffer zones adjacent to World Heritage sites, as defined by the national government and UNESCO, do not jeopardise the Outstanding Universal Value for which these sites are listed.

"Soco confirms that when we undertake environmental impact assessments and human rights due diligence, the processes we adopt will be in full compliance with international norms and standards and industry best practice, including appropriate levels of community consultation and engagement on the basis of publicly available documents."

However, in a statement today the Church's Ethical Investment Advisory Group said: "Following board level engagement between the Church of England Ethical Investment Advisory Group (EIAG) and SOCO International Plc (Soco), the EIAG has raised serious concerns about the Company's determination to satisfactorily address, in an open and transparent manner, allegations concerning the operations of Soco in and around the Virunga National Park in the Democratic Republic of Congo (DRC).

"These allegations are of a serious nature and require a response from the board that urgently seeks to restore the confidence of shareholders. We find the efforts of the company to date have not been sufficient."

Steps the company needs to take to restore confidence include "a wide ranging and transparent independent enquiry of Soco's operations in and around Virunga National Park", the Church said.