MONTREAL -- Quebecers who do not comply with public health guidelines amid the COVID-19 pandemic -- particularly, those who don't wear masks inside public places and on public transit -- will now be subject to fines up to $6,000.

The measure came into effect on Saturday, but Premier Francois Legault made the announcement at a press conference in Quebec City on Thursday morning alongside Health Minister Christian Dube and the province's director of public health, Dr. Horacio Arruda. The decree specifies that masks must be adjusted properly so the nose and mouth are both covered.

"It is important to say that still today there is a very vast majority who follow the guidelines of public health, but unfortunately there is a small minority of irresponsible people who are not following the guidelines, and these people are putting many things at risk," Legault said. 

Legault did not say at first how much fines would cost -- adding that Minister of Public Safety Genevieve Guilbault would announce that later -- but he said they would be high enough to encourage people to wear masks. 

"The purpose is that the fines will deter people from not respecting the guidelines," he said. 

Guilbault followed through on Friday afternoon, announcing on Twitter that the fines will go up to a whopping $6,000 per offence. She didn't say what kinds of behaviour will net people smaller or bigger fines on the scale the province has set out.

"The vast majority of Quebecers respect health rules and I thank them for that," Guilbault wrote.

"For the recalcitrant, the fines for refusing to wear a mask in indoor public places will range from $400 to $6,000. This tool will be available to police from tomorrow."

The measure will apply across the province, but the government is asking police officers to pay particular attention to regions labelled yellow on Quebec's new regional alert system and to increase their presence in closed public spaces. As of Saturday, the regions labelled yellow are Quebec City, the Eastern Townships, Outaouais and Laval. 

Legault also asked citizens to be vigilant about each other's behaviour.

"And obviously, we're asking the population -- when they see something out of line -- to call 911," Legault said. 

"There's a trend that we don't like here, and right now we cannot accept that a few irresponsible individuals put at risk our entire society in Quebec, so I think it is now time to clamp down on these people," he added. 

Despite a recent upward trend in daily cases across Quebec and 18 new hospitalizations over a three-day period, Legault said "I think that we are still in a situation that is under control."  

He added on Thursday that a province-wide lockdown is not being considered at the moment, but certain things -- like karaoke events in bars -- may be restricted, after a recent outbreak in Quebec City was traced back to a karaoke event. A ban on karaoke was then announced on Friday.

The province has no plans to close bars entirely, Legault said. 

Legault defended his recent trip to Ontario to meet with Premier Doug Ford after receiving backlash for dining with him in a closed space. 

"All the rules were respected in Toronto -- when we were inside, we wore masks until we were sitting down two metres away from one another," he said. "All public health measures were applied." 

On Wednesday, Montreal's director of public health, Mylene Drouin, said several cases in the city have been linked back to private gatherings where guidelines haven't been followed. 

“Parties, dinners, weddings, and social activities after (playing) sports with friends,” she said. “It’s really in those events we can see there is transmission going on.”

"We ask people to be more vigilant when they are in social activities and to follow the public health recommendations," she added. 

--With files from CTV's Selena Ross