Speedy Hire, an equipment hire company, has appointed Deloitte to do a "forensic investigation" after finding accounting irregularities of up to £5m in the accounts of its international division.
In November the Merseyside-based company, which hires equipment to industries including construction, rail and utilities, said it had found that "certain control processes within the international division have been repeatedly and deliberately circumvented".
The irregularities, which are expected to cost between £4.5m and £5m, are believed to affect a limited number of smaller contracts, Speedy Hire said.
Pre-tax profit is likely to be reduced by £3m.
in November, Speedy Hire said that it's chief executive, Steve Corcoran, would resign. The finance director of the international division has been suspended.
Speedy Hire has also appointed law firm Addleshaw Goddard to do an independent legal investigation.