HALIFAX -- If you've been putting off mailing gifts for the holidays, your deadline to get them to the post office can be measured in hours rather than days.

Dealing with unprecedented demand, Canada Post revised its shipping guidelines Monday, and there isn't much time left.

Allan Snelgrove was one of many who went out on his lunch break on Monday to run that errand they've been putting off.

Just 10 days from Christmas Eve, it's not surprising there are others on the same mission.

Even so, he's not overly optimistic his items will arrive before Dec. 25th.

Canada Post isn't mincing words: demand this year is "unprecedented," it says.

More Canadians than ever have embraced online shopping, and with get-togethers limited, they are shipping presents rather than showing up.

More than a million parcels were delivered over the weekend alone.

"We knew this was going to be an incredibly busy peak season," said Jon Hamilton of Canada Post. "It's been even busier than we anticipated."

Even with 4,000 extra workers and a fleet of rented trucks, he says there's a limit to what it can safely process and deliver, and Canadians should expect delays.

Annual shipping deadlines were revised Monday morning.

Even if you're paying extra for faster delivery, Friday is about your last hope of seeing it arrive before Christmas. The deadline is earlier if you ship at regular rates.

"We know people are paying very close attention to those deadlines," Hamilton said. "That's why we've changed them to ensure that, if people are looking at them, they can get their best sense as to how they can help us out if they're looking to get their item there before Christmas."

A similar line from the private couriers, who say, they, too, have beefed up capacity, but customers are advised to shop and ship early during an unprecedented surge.

For the most part, people understand.

"It's the new normal, and, at the end of the day, it's got to be done right to keep everybody safe," Snelgrove said.