Ontario Premier Doug Ford attends press availability in Markham, Ontario, on Friday July 24, 2020. THE CANADIAN PRESS/Chris Young

With the unofficial end of summer upon us, Ontario Premier Doug Ford is urging citizens to keep their Labour Day parties small and safe this long weekend.

Speaking on Newstalk 580 CFRA's "The Morning Rush with Bill Carroll", the premier said he's concerned about the rising case numbers in Ontario.

"I'm concerned. I'm really concerned to see the numbers just slowly creeping up," he said.

Health officials reported 148 new cases of COVID-19 in Ontario on Friday, with 72 of those cases in the Peel Region.

"The Peel region public health officer was out there and he said there's a lot of parties happening in back yards without face masks," Ford said. "Right after he said it, a couple days ago to us, bang, we see a massive increase in the Peel, Brampton area."

"Folks, I can't stress it enough: please, if you have small group over, wear a face covering and enjoy yourselves but I'm just really concerned if this starts spreading again."

The 72 new infections reported in Peel Region on Friday is the highest single-day tally recorded in that area since June 4. The region had seen its daily case counts fall to the low teens as recently as early August, but since then they have been recording a steady increase with their rolling seven-day average now at 36.

"It gets concerning when we're below 100 and all of a sudden it starts creeping up again," Ford said.

He said he was also worried that flu season will soon be upon us.

"That's another concern, the flu season at the end of September, October, November. We have to be so vigilant. We can't take our eye off the ball for a second on this," he said.

In Ottawa, 13 new cases were reported on Friday, down from 22 the day before. The number of new cases reported in Ottawa each day has been hovering around the low double digits for much of the last month, with the rolling seven-day average at 16, presently. Active cases have been hovering around 200 for the past week, after dropping to a low of 108 for the month of August.

Ford's request to keep parties small and limit COVID-19 spread comes as students around Ontario start getting back to class. Ford has previously said he would not hesitate to close schools down again should COVID-19 spread rapidly.

Speaking on Newstalk 580 CFRA, he stressed he would follow the advice of health experts.

"If I didn't think it was safe, and I've proven that to the people of Ontario, I'll shut it down in ten seconds," he said, referring to the decision to close schools in March after March Break.

"If there's an outbreak, that's it, we're closing it down in a heartbeat. It really comes down to community spread and classroom spread. If one child gets it or two, I'm going to leave that up to the health experts. If we hear there's a breakout, we'll determine what sort of breakout it is and, from there, we'll make our decisions."