The deaths were not concentrated in any specific municipality.
In 2010, a heat wave killed around 100 people in the Montreal area.
"It could save a life", Genereux said.
Local authorities are taking initiatives to combat the heat, including opening swimming pools and air-conditioned areas to the public, distributing water and having first responders checking in on vulnerable citizens.
Humidex values this week were expected to reach as high as 43 C in southern Ontario, and Environment Canada issued a heat warning for the densely populated region.
He said the Montreal heat exposure victims were between 50 and 80.
Six more people have died in Montreal due to a heat wave, bringing to 12 the city's total death toll from the extreme weather conditions that have gripped central and eastern Canada, health officials said on Wednesday.
L'autopsie de Maëlys contredit la version de Lelandais
La dépouille de Maëlys a été rendue à ses parents fin mai et les obsèques ont été célébrées début juin, neuf mois après sa mort . Selon BFM TV , les experts ont acquis la certitude qu'aucune des fractures qu'ils ont relevées n'est à l'origine de la mort.
Southern Quebec was rocked by violent storms on Monday, leaving thousands of homes and businesses without electricity, or air conditioning.
"My thoughts are with the loved ones of those who have died in Quebec during this heat wave", Prime Minister Justin Trudeau said on Twitter.
"We go out to the paramedics, we go out to the hospitals and we ask them to make sure to identify any deaths they believe are related to heat and that allows us to intervene more quickly", Kaiser said.
No deaths have been reported in other provinces.
The move is part of the federal government's climate change adaptation in expectation of more frequent heat events.
According to Environment Canada, the daytime high in Toronto will be 31 C on Tuesday, 32 C on Wednesday, and 32 C on Thursday.
Montreal's emergency medical service says it has received an influx of 300 more calls than usual.