LONDON- Five human rights advocacy groups on Tuesday called on the European Union not to endorse the most important accreditor of gold refineries, a move that would create headaches for European bullion importers.

The EU is assessing whether schemes which certify that refiners are sourcing gold responsibly conform with conflict minerals regulation that came into force in the bloc this year.

If the EU recognises existing accreditations it will be simpler for importers of gold to show that they comply with the regulation.

The biggest accreditation scheme for gold refineries is run by the London Bullion Market Association (LBMA).

In a letter to the LBMA and to European officials, organisations including Global Witness and SWISSAID chronicled what they said were gaps and failures in the LBMA accreditation scheme and said the EU should not endorse it.

"The LBMA's claim that its Responsible Sourcing Programme is robust and that all the gold it certifies is free of human rights abuses is simply not credible," said Anneke Van Woudenberg at RAID, one of the signatories to the letter.

The LBMA did not respond to a request for comment.

A source at the European Commission, the EU's executive arm, said the assessment of the LBMA's accreditation scheme was ongoing and the commission could not comment further.

(Reporting by Peter Hobson, editing by Louise Heavens) ((Peter.Hobson@thomsonreuters.com; +44 207 542 0083;))