Toronto saw more than 500 opioid overdose deaths in 2020, a record number that the city's top public official said Wednesday is worrying.

According to preliminary data from Ontario's coroner's office, 521 confirmed opioid overdose deaths were recorded in last year, a 78 per cent increase from 2019 and a 280 per cent increase from 2015.

"This is just yet another tragedy on top of the tragedies that we have suffered through COVID-19," Dr. Eileen de Villa, Toronto's medical officer of health, said in an interview with CP24.

"I cannot tell you enough how disheartened I am and how concerned I was to see the numbers in respect of opioid overdose-related deaths."

Many public health officials and advocates have said that the coronavirus pandemic has exacerbated the opioid crisis.

TPH said that Toronto paramedics were getting an average of 13 calls per month for suspected fatal opioid overdoses before COVID-19 hit. However, it has increased to 26 calls per month during the pandemic.

"It is very much still a concern in our minds. Obviously, addressing it has been made more challenging as a result of the number of measures that had to be put in place in order to manage the COVID-19 pandemic," de Villa said.

"So, lots of work for us to do on this front."

Earlier this month, the city saw its "worst cluster" of suspected overdose deaths since TPH began collecting data in 2017, including a record of five suspected opioid overdose fatalities in a day.

TPH said Drug Checking Services has also detected an increase of toxic and unpredictable contaminants in the unregulated drug supply in the city.

To address the worsening crisis, TPH said it is coordinating and providing evidence-based harm reduction support at city hotels and shelters and expanding supervised consumption services.

"Any life lost to a drug overdose is preventable and thus unacceptable. The experts are clear that harm reduction programs will save lives and that's why the city and Toronto Public Health has worked to implement those programs in our city with the help of the Government of Canada," Mayor John Tory said in a statement.

"I am determined to keep working with the other governments to help people with substance use issues, to expand treatment programs, and to save lives. Much of this should properly be done by our healthcare system and I look to the province for increased initiative."

Earlier Wednesday, a report from the Ontario Drug Policy Research Network found that fatal opioid overdoses were up more than 75 per cent last year. Between March 2020 and December 2020, 2,050 people in Ontario died of opioid overdoses – the vast majority were accidental.

Dr. Tara Gomes, one of the authors of the report, told CP24 that they wanted to look at how fatal overdoses have changed since the pandemic began.

"I've seen that they have increased dramatically. There's nearly an 80 per cent increase in the number of opioid-related deaths between March and December of 2020. And that the circumstances around those deaths are really changing as well," Gomes said.

"The drug supply is increasingly unpredictable. People are dying, and they're alone. They are not able to always access the same degree of services that they were able to in the past. I think that all of that is really coming together to create a really dangerous environment and one where we're seeing a tragic circumstance of huge loss of life throughout the pandemic due to opioid overdose."

- with files from the Canadian Press