Cannabis was legalized in Canada on October 17 and there are some concerns over supply after sales skyrocketed but the province says it is working with producers to ensure they keep up with demand.

The Alberta Gaming Liquor and Cannabis Commission says more than 28,000 people have registered to buy products online and that there has been almost $750,000 in sales so far.

People lined up around the block at Four20 Premium Market and Nova Cannabis during the first few days of legalization and the Four20 store ran out of cannabis oils for a couple of days this week.

"It's just going to take time for the system to continue to work and licensed producers to ramp up and produce more product. We're going to see some ups and downs in supply for likely several months,” said Ryan Kaye, VP Operations, Four20 Premium Market.

The retailer is one of a handful of stores that are currently open in the city and more stores are expected to open in the coming days.

On Wednesday, Calgary Co-op launched its cannabis division and opened a store on Macleod Trail.

Co-op plans to be one of the largest cannabis retailers in the country and will open more stores over the next year.

Nearly 800 applications have been filed for retail cannabis licenses across Alberta. Of those, 226 are in Calgary and 147 are in Edmonton.

The AGLC has issued 33 cannabis licenses in Alberta but not all of the stores are open yet.

More than 100 cannabis retailers will open across the province in the next month and the AGLC says it expects to licence 250 stores over the next year.

Cannabis can be bought at licensed stores or online HERE.

For more information on cannabis store locations, click HERE.

For complete coverage of cannabis legalization in Canada, visit our Marijuana Legalization in Canada page HERE.