Tory Leader Brian Pallister says Steve Ashton may have broken the rules for awarding contracts and calls it "an undeclared conflict" that has created doubts in the minds of many.
Premier Greg Selinger is defending Ashton and says it is Pallister who may have something to hide.
He says Pallister "seems to try to avoid responsibilities for the policies he wants to put forward," suggesting the Tories would be in favour of privatizing day care and other social services.
An anonymous whistleblower complaint reported by the Winnipeg Free Press last week alleged Ashton pushed to have the contract to provide flood-fighting equipment awarded to a company that supplies water-filled tubes called Tiger Dams.
The whistleblower alleged two officials from the company have been Ashton campaign contributors and Ashton wanted to bypass the normal requirement to allow other companies to bid on the work.
Both Ashton and Selinger have denied the allegations. Last November, the contract was put up for open bidding. It has still not been awarded.