Canada has a major bummer on its hands: a marijuana shortage.

The country’s pot smokers, who have long been psyched about Prime Minister Justin Trudeau’s plan to legalize weed nationwide next year, are now facing a painful paucity of the stinky, combustible herb.

Vancouver-based Lift, a marijuana media platform in Vancouver, estimates Canada’s cannabis industry has enough funding to boost production to between 400,000 and 500,000 kilograms a year.

But Lift CEO Matei Olaru told The Post the demand for pot is expected to reach 655,000 kilograms during the first year alone of across-the-board legalization.

The shortage could be so severe that medical users could be pushed aside when recreational use becomes legal next year, according to weed watchers.

Medicinal users, who after tripling in number last year to 170,000, will feel the brunt of any deficit, according to the firm.

Some worry that persistently high prices for legal pot could allow black-market weed to flourish — undermining a key reason for Trudeau’s 2015 campaign to legalize it in the first place.

Trudeau, who’s aiming to make pot legal nationwide in July 2018, admits much needs to be done before Canada becomes the first developed country to legalize pot for recreational use.

His “Framework for Legalization,” released in April, addresses but does not resolve such issues as minimum age (somewhere between 18 and 25), impaired-driving limits and maximum potencies for THC, pot’s principal psychoactive ingredient.