The white collar police have widened their probe into a unit of Singapore-listed Magnus Energy Group.

In a statement on Wednesday, Magnus said it had been notified that the Corrupt Practices Investigation Bureau (CPIB) had expanded its investigation into "plausible inappropriate gratification" at the unit.

In May last year, Magnus said a former employee of the subsidiary, in which it owns a 27.18 per cent stake, had misappropriated inventory worth about US$202,800.

The firm had been paid an order by a customer in 2007, and on the customer's instruction, the goods were delivered to a third party warehouse.

In 2009, the former employee gave verbal instructions to the warehouse to release the goods to an unknown party.

Though the standard procedure required a written release instruction from the company to the warehouse as proof that the title of the goods had been transferred to the customer before inventory could be released, no such written instruction was provided in this case.

The unit has refunded the customer and the former employee, through a legal representative, has reimbursed the firm in full.

In its statement, Magnus said it was unable to provide more information about the expanded probe "as the details on the investigations is unknown".

The firm added that to the best of its knowledge, none of the management personnel or the directors of the subsidiary and Magnus itself have been formally implicated in the investigation.