KITCHENER -- At the beginning of the pandemic it wasn't unusual to see items out of stock, like toilet paper and flour.

Now we're seeing a similar situation as the Omicron variant spreads.

Staff absenteeism and supply chain issues are putting pressure on grocery stores, and they're having to work even harder to make sure shelves stay stocked.

Customers at Central Fresh Market in Kitchener have noticed some changes.

"[We're] definitely seeing a bunch of different supply chain issues," said manager Brent Kapuscinski.

Stores across the country are also noticing similar issues.

"This is a consequence of COVID-19, and particularly, with Omicron," said Peter Carr, a management sciences professor at the University of Waterloo. "There are a lot of people not at work because they are sick, or they're isolating."

According to the Canadian Federation of Independent Grocers, some stores are reporting about 30 per cent employee absenteeism due to COVID-19 protocols.

"Or they are not working because of 'the great resignation,'" Carr said. "You know, as we've moved through COVID, a lot of people have gotten tired, specifically in supermarkets and in food processing."

There's also what's being called the “lockdown effect.”

"We're buying more because we're not going to restaurants," explained Carr.

"Warehouses are ravished by COVID as well, so there's less pickers," Kapuscinski said.

He's also noticed a lack of truck drivers.

"For years we get it from the same place, now I'm calling three or four companies to see if I can source it out from there."

While some deliveries may be delayed, they are still coming, and experts say there's no need to panic buy.

"The main thing we are going to see inside the shops is less variety," said Carr.