OTTAWA -- Prime Minister Justin Trudeau says it's natural for people to be "a little confused" about what they can and cannot do as the economy begins to reopen, but warned that we must remain smart to avoid a resurgence of COVID-19.

His comments come just after thousands of people packed Toronto's Trinity Bellwoods park over the weekend, breaking physical distancing rules in swarms on one of the first warm days of the year.

"It's natural for, as we begin to see the economy reopening, for people to be a little confused about what it is they can do…what it is they shouldn't do, and that’s why we're really going to continue to impress upon people the importance of making smart decisions," Trudeau said, speaking from the front steps of Rideau Cottage on Monday.

He explained that different communities will have to tailor their own approaches to the realities they're facing, which can be a source of confusion for Canadians as they see neighbouring provinces or cities following a different set of physical distancing guidelines.

"The rules and public health recommendations you're asked to follow may be different depending on where you live. And that can be confusing," Trudeau said.

"But, right across the country, one thing will stay the same: Everyone has a responsibility to themselves and to the people around them. So keep practicing physical distancing. This is how we protect ourselves, protect our loved ones, and protect the most vulnerable."

The prime minister explained that even though Canada is making "progress" in the fight against COVID-19, the situation remains "very serious."

As of Monday, Ontario had seen its COVID-19 case count rise above 400 for five days in a row. Over the course of the pandemic, Canada has seen more than 85,000 cases, 44,000 recoveries and more than 6,400 deaths — and there are still many active cases across Canada.

Meanwhile, experts are warning that a second wave isn’t so much a matter of if, but when.

"The second wave will come, but how acute it is or how large it rises so it doesn't overwhelm our health-care system needs to be considered," Dr. Sandy Buchman, the president of the Canadian Medical Association, told CTV News Channel last week.

This was the logic that drove the initial lockdown. Canadians shuttered their business doors and began to physically distance from those outside their households in order to prevent a surge in cases that our health-care system couldn't cope with. Now, as experts warn of an inevitable second wave, they say it's essential to put in place measures to track the spread of the virus.

"We need to gather more information, we need to do adequate testing in our communities, we have to do more contact tracing, and ultimately we have to do serologic testing," Buchman said.

Meanwhile, Infectious Disease Expert Dr. Abdu Sharkawy says there are also steps that individuals can take to fight the spread of COVID-19 — practice physical distancing, and follow public health measures in your area.

"Every single person in our community is accountable in terms of their behaviour and how it puts others at risk. So this is a shared accountability, we're all in this together," Sharkawy said.

Meanwhile, Ontario Premier Doug Ford has encouraged all those who gathered at Trinity Bellwoods Park over the weekend to go get tested after their "reckless" behaviour.

"First of all, I'm disappointed to say the least with everyone who showed up at Trinity Bellwoods on Saturday," Ford said at Queen's Park on Monday. "Why don't you do us all a favour and go get tested now, go to a local hospital or assessment centre and get tested."

"I encourage anyone who has been in large gatherings like that...they need to get tested."

With files from CTV's Ryan Flanagan and CTV's Sean Davidson