Booking a COVID-19 test at a local assessment centre may take longer these days as the sites deal with staffing shortages.

Demand for testing has grown as cases climb.

"We are starting to see an increase in the need for testing," said Lee Fairclough, the president of St. Mary's General Hospital.

Staffing shortages are making it more difficult to get an appointment.

"It is harder to book on the day of," said Stephanie Pearsall, testing lead for Waterloo-Wellington. "For the next day, there's definitely more."

Kitchener's drive-thru testing site, which is run by Grand River Hospital, almost had to close on Saturday.

"There was some concerns that it would not be open, but we have secured an external vendor to come and do some testing on-site at the drive-thru," Pearsall said. "That's through Ontario Health."

Cambridge is also feeling the staffing crunch.

"I know the Cambridge site specifically is trying to secure additional staffing for (Saturday) and Sunday to open up additional appointments," Pearsall said.

Pearsall said the shortages are linked to sick days. Transfers have also played a role.

"Our nurses from our testing centres are coming to work in the hospitals in other roles," Fairclough said. "I think we just need to continue recruiting in that area."

Fairclough said vaccine policies are not a factor.

"I think the consideration of our vaccine policy is quite separate to this," she said.

Officials said people skipping appointments without cancelling has also been an issue.

"I think it was Grand River on Monday that had 100 appointments that were booked and people didn't show up," Pearsall said.

Health officials are asking people to cancel appointments if they get one at a different location or no longer need a test.