Scorching summer weather in Japan has led to at least 132 deaths and seen more than 30,000 people rushed to hospital with heatstroke, the government said Tuesday.

The mercury has repeatedly topped 37 degrees Celsius (99 degrees Fahrenheit) in recent days in central Tokyo and other locations in Japan, and the sun continued to blaze down as the figures were released.

"Being outside in this heatwave for a long time is quite dangerous," said Yukie Ito, a Fire and Disaster Management Agency official in charge of heat-related incidents. "We should not underestimate the heatwave."

The agency said 31,579 people nationwide were sent to hospital with heatstroke between May 31 and August 15, the highest number since the agency started keeping figures in 2008.

Nearly half of them were aged 65 or over.

At least 132 people were confirmed dead immediately after they reached hospital, the agency said, and more people were believed to have died later.