The minister responsible for the Saskatchewan Transportation Company says the Crown corporation is investigating a potential privacy breach of its freight customers.

The government announced in its spring budget that it is shutting down the 70-year-old bus service.

Minister Joe Hargrave said he recently learned that a private company, Carpe Diem Limousine Service, has been writing to STC freight customers.

"It was our understanding that Carpe Diem had somehow obtained a list of these people and had started to send out letters and soliciting and made out that they were affiliated with us," he told reporters.

"We have no affiliation whatsoever and never have had with Carpe Diem."

He said STC wanted people to know this, so it has followed up with a letter to 2,845 STC customers.

CBC reached the Carpe Diem office Thursday morning for comment.

"We'll talk next week. (The government) can put out what they want. They're the ones who closed down STC. That's not on us," someone said.

They declined further comment and then hung up.

'This is a serious matter': Wotherspoon

Opposition leader Trent Wotherspoon notes this is not the first time Carpe Diem has appeared to presume it will take over from STC.

"This is a serious matter. The question is: How did that company access that information?" Wotherspoon said.

He noted Carpe Diem has already been advertising for drivers for what it described as its "new STC freight division."

Hargrave said STC has told the limo service to "cease and desist using our name in any of their letters or any of their advertisements online."