The city of Seattle is to reopen an inquiry into whether it was overcharged by Office Depot, according to the Seattle Times.

The action comes as a former Office Depot employee turned whistle-blower, David Sherwin, said that based on audit findings from other government contracts, Seattle could be owed more than $1 million.

Although Office Depot has denied any wrongdoing, it has settled claims including $4.25 million to San Francisco this year and $5.9 million to Florida in 2010.

Office Depot spokesman Brian Levine said: "We're not aware of any issues brought to our attention with the city of Seattle."