TORONTO -- Ontario recorded its highest number of coronavirus infections since early June on Monday as the Ontario Hospital Association (OHA) warned that the province is "losing ground" in its battle against COVID-19.

In a press release issued on Sunday, the OHA, which represents the province’s public hospitals, implored Ontarians to continue following public health measures "that are essential to saving lives and preventing a second wave of this deadly pandemic."

"Daily case growth is now over 200, a clear warning sign that our hard-won progress is slipping away. It is the responsibility of each of us to take steps immediately to halt this alarming trend," OHA president and CEO Anthony Dale said in the release.

Ontario health officials reported 313 new COVID-19 cases on Monday, marking the province's highest daily total in 14 weeks.

The spike in cases comes after health officials reported an increase of more than 200 new cases of COVID-19 on Sunday for the third straight day. Most cases appear to be in the Toronto, Peel, York and Ottawa regions, according to health officials.

In a tweet on Saturday, University Health Network president and CEO Kevin Smith said that the Toronto-area hospital group now has seven COVID-19-related admissions, after having none for weeks. He said most of the admissions are in intensive care.

CTV Infectious Disease Specialist Dr. Abdu Sharkawy retweeted Smith and added that once COVID-19 enters the hospitals and ICUs, "it signals uncontrolled community transmission."

"This is NOT a blip. It's real. PLEASE be responsible. Be vigilant before it's too late! Nobody wants #Lockdown2," Sharkawy wrote.

Last week, Ontario Premier Doug Ford said in a press briefing that local medical officers should consider re-imposing coronavirus restrictions if needed.

The OHA echoed the same sentiment, saying Ontario’s economy may be forced to shut down again if case numbers continue to rise.

"Without continued vigilance, [Sunday’s] isolated outbreaks in Toronto, Peel, York and Ottawa could easily spread throughout communities right across Ontario," Dale said. "If current trends continue to accelerate, economic restrictions may tighten once more, and the school year for our children will be in jeopardy."

Spiking COVID-19 cases in B.C. prompted the province to shut down nightclubs and banquet halls last week while bars and restaurants had their hours reduced. Ontario has not reversed course on its reopening but the provincial government has deferred any further loosening of restrictions for at least four weeks.

However, infectious disease specialist Dr. Sumon Chakrabarti told CTV News Channel that Ontario still has time to flatten this new wave in its curve.

"I still maintain that a full lockdown like we saw in March is very unlikely because that was a time when we saw this tidal wave coming and we had nothing else to do," Chakrabarti said in an interview on Monday.

"But at this point in time we can see the wave forming. When it's small, we still have lots of time to do targeted interventions."

Chakrabarti explained that 200 infections a day back in March is "very different" than seeing 200 cases in September. He said that Ontario was only testing severely ill patients back in March but now, the testing is "a lot broader."

"Yes, this is concerning. Yes, we need to address this, but I think we should put this into perspective. We're still in a good spot, we still have time," Chakrabarti said.

In the press release, Dale reminded Ontarians that it is the "personal responsibility" of everyone to "strictly adhere to the public health measures."

He said Ontarians must continue to wash their hands frequently, practice physical distancing, wear face masks when required, stay home when sick, and neither host nor attend unsafe gatherings or parties.

"We are all in this together and our collective success depends on each of us making the right choices. Ultimately, skipping a dinner party or a wedding that isn’t safe is a very small sacrifice to make to protect our loved ones and people who are particularly vulnerable to the threat of COVID-19," Dale said.