The Regina Qu'Appelle Health Region said Wednesday it was postponing surgeries at the Pasqua Hospital, one of two hospitals in the capital.
Health region CEO Keith Dewar said a team was working to identify the root cause of the problem and how to fix it.
He also said patients weren't at risk and the equipment is considered clean.
"Every piece of equipment that goes through the sterilizing process has a chemical indicator or sterility indicator in there," Dewar told a news conference. "As long as that sterility indicator passes, you know that it has been properly heated and steamed to disinfect and ensure that the equipment is proper for use."
The health region said Tuesday that staff doing quality control assurance weren't able to ensure surgical equipment was properly sterilized and so cancelled 16 surgeries for Wednesday.
Officials had initially expected the issue to be corrected within a day.
At issue is a discolouration that has been found on cotton packaging that is wrapped around surgical tools during decontamination. The final step in disinfection involves a steam-based sterilizer.
"We believe (the discolouration happens) in the process somewhere between where the steam is created and where it comes and meets up with our sterilizing equipment," Dewar said.
"That discolouration doesn't mean it's not sterile. It's just there was discolouration in the wrap around the pack that we're not too sure what's causing it, but we believe its through the steam that's coming in."
Dewar said staff had noticed the discolouration twice before this month.
Postponing surgeries for up to 10 days could affect up to 150 patients, although only elective operations will be pushed back. Dewar said urgent and emergency surgeries will be done at the General Hospital.
The health region has started contacting any patients whose surgeries will be affected.