Parents in Canada could be facing a shortage of car seats in the new year as new design regulations take effect.

Car seats are about to get bigger because of the new safety regulations from Transport Canada. The seats will be widened and lengthened and the weight limits will rise, so that babies will stay in rear-facing infant seats until they reach 10 kilograms (up from the current nine), while weight limits for forward-facing seats will rise to 30 kilograms, up from 22.

The new seats will also have more padding to accommodate the new generation of chubby babies.

The changes are driven in part by the fact children have gotten heavier over the past two decades.

"The babies are bigger and longer and when they're rear facing when they're an infant, their feet have a tendency to touch the back seat," Gad Bensabath of Pinkiblue, a Montreal store that specializes in products for babies and toddlers, told CTV.

The changes will also put Canada's regulations in line with those of the U.S.

After Jan. 1, 2011, car seat manufacturers will only be permitted to sell seats that comply with the new standards. While parents will still be able to use their current car seats after the new regulations take effect, it's expected that many will choose to wait for the new car seats rather than use seats they may perceive as "outdated."

That build-up in demand could spark a shortage of car seats early next year, said Glen Cockburn of Britax, a stroller and car seat manufacturer.

"There hasn't been enough time for a lot of manufacturers to get compliant with the new regulations," he said.

Delays in testing the new car seats have compounded the problem. Canada has only one qualified compliance testing centre to approve new car seat models, and the location is booked until mid-March. Another testing facility was recently set up in Montreal, but it's not fully up and running.

As a result, companies likely won't be able to get enough car seats on to store shelves early next year.

That's left manufacturers and retailers lobbying the government for more time to comply with the regulations.