The chief executive of the world’s largest non-governmental money printer De La Rue Plc stepped down after the firm warned sales would be hit by quality problems at one of its paper factories.

“Mr Hussey’s decision to resign follows the company’s statement … in relation to certain quality and production irregularities at one of its paper production facilities and his belief that he must take responsibility for this,” De La Rue said in a statement.

“The company continues to look into these irregularities in one of its paper production facilities, which the board considers to be of a serious nature,” the statement added.

In July De La Rue, which prints dozens of currencies as well as passports, warned that sales in 2010 and 2011 would be “materially lower” than expected after it suspended production at a paper factory.

De La Rue said it would reveal the impact of the suspension on its financial results as soon as its board has made an assessment, but this was unlikely to be in the near future.

Earlier in the year, spokesman for the company said the factory involved was one of its largest producing bank notes in Overton in southern England.

De La Rue said in the statement it was confident that the physical security or the security features of the paper produced at the factory had not been compromised. A spokesman for the company declined to comment further.

Nicholas Brookes, non-executive chairman, has been appointed executive chairman, and finance director Colin Child has taken on the additional job of chief operating officer until Hussey’s replacement is named.