Antonio Serra, 77, died after collapsing on a beach in Cagliari, Meteoweb reported, while a 48-year-old Romanian died while fishing in Verona province.
The Romanian died just days after another man collapsed in the heat while working in fields in Belfiore, a town in Verona, Ansa reported.
Last weekend, two cyclists from Bergamo died, along with three other elderly people at beaches in the Emilia-Romagna region, as temperatures topped 40 degrees Celsius.
A 77-year-old also died while cycling with a group of friends in Chivasso, Piedmont, last Thursday, Fanpage reported.
The other victims included an 87-year-old man, who died on a beach in Imperia on Saturday morning, and another elderly man, who died while at the beach in Diano Marina, slightly further down the Ligurian coast, on Sunday morning, SanRemoNews reported.
Meanwhile, a 76-year-old woman collapsed and died while in the sea in Pescara, according to a report on GELocal.
The heatwave, which is expected to last until Thursday, prompted the Italian Health Ministry to activate its summer telephone hotline - 1500 - for heat-related emergencies and advice.
A heatwave in 2012 was responsible for the deaths of 15 people in Italy, while 500 were hospitalized.
Meanwhile, 3,100 people died in Italy during a heatwave in 2003 that lasted for three months. The whole of Europe sweltered that summer, causing more than 20,000 deaths across the continent.
But as high temperatures lingered, the outskirts of Venice were struck by a typhoon on Wednesday, killing one and injuring over 30.
The storm was captured on video.