Irish food group Greencore said on Wednesday it had uncovered a "deliberate concealment of costs" at its mineral water business leading and it would restate some earnings lower.

Greencore, which ranks itself as Britain's biggest sandwich maker, said the group's senior management was informed about concerns on June 6 after an audit review.

Greencore said its investigation showed the concealment of costs had been carried out by the former financial controller of its mineral water unit who left the business before the matter was uncovered.

The company said the concealment had led to a "material misstatement of financial performance" in 2006, 2007 and the current financial year.

"The board of Greencore believes that the financial implications of these issues will lead to a restatement reducing the group's operating profit by 4 million euros (3.1 million pounds) for 2006 and by 8 million euros for 2007," it said.

"In addition, the estimated impact of this issue in 2008 will be a reduction of operating profit of 9 million euros relative to current expectations, with a consequent impact on adjusted earnings per share of 4 cents."

Greencore said while its board believed it was an isolated issue, it was conducting an independent review of all its businesses and auditing processes.

"Since this issue was first identified, the priority of the board has been to move quickly to determine the cause, extent and impact of the concealment," it said.

"Apart from adjusting for the impact of this material misstatement, the board, based on current trading, remains confident that it will meet consensus market expectations for 2008 EPS performance," it said.