There's a new weapon in the city's battle against illegal pot dispensaries: giant cement blocks.

Two photos posted to Reddit show the blocks stacked up in front of alleged cannabis dispensaries, blocking entry.

It's the latest move to put a stop to illegal dispensaries that have been able to operate thanks in part to a legal loophole in the province's Cannabis Control Act.

That loophole has prevented authorities from barring access to, and removing people from, suspected dispensaries that were also being used as residences.

"This has proven to be a bit more of a substantial tactic," said Mark Sraga, the city's director of investigation services for municipal licensing and standards.

Illegal cannabis storefronts have persisted in Toronto despite raids and attempts to bar the stores' entryways using other means, including steel doors. Sraga estimates about a dozen are still in operation despite enforcement measures.

Bill to close loophole passes at Queen's Park

But on Thursday, a bill aiming to close the loophole — by removing the exception around dispensaries that might also serve as residences — received royal assent, despite objections from some MPPs.

NDP MPP Jeff Burch, for example, raised concerns that a family could be expelled from their home because another relative, or even a visitor, was selling cannabis.

"We have some concerns on what this will mean for families," he said.

"Cannabis is currently legal, and while the illegal sale of cannabis should be prohibited, giving the ability for a family to be expelled from their home because a family member —or worse, a visitor — engages in an illegal activity is unthinkable."

"Going forward, a residential property that's being used to sell cannabis illegally, we will also be able to doing barring of entry at those places," said Sraga.

But blocks won't necessarily come to all pot shops.

Not all convinced blocks are the right move

Sraga says officers had previously investigated the locations and taken enforcement actions against them, including securing and locking their doors, and only resorted to this step on May 25 after illegal sales continued.

So far, the city has seen about an 85 per cent compliance rate with their store closure efforts, he says.

But not everyone is convinced the blocks are the best measure.

More blocks were spotted near Yonge and Bloor streets. (Kandoh/Reddit)

Criminal defence lawyer Kendra Stanyon says there are questions about where people will go if they're barred from dispensaries that are also their residences.

But Sraga says he's seen some illegal pot shop operators place beds inside their locations to try to claim they in fact live there.

And while pot shop employees have been arrested and charged in the past, Stanyon thinks that too is a "waste of resources."

Instead, Stanyon says enforcement officers should be going after the owners themselves.

"It seems less effective than going after the actual registered owners of a dispensary if they so choose, and laying criminal charges."

She believes the persistence of illegal pot shops speaks to the demand for cannabis in the city.

"There is such a shortage online and in stores for legal marijuana that, setting aside issues of quality ... the demand is still very huge for the black market."