Greece will endure a three-day heatwave starting Tuesday with temperatures exceeding 40 degrees Celsius (104 Fahrenheit), the country's civil protection minister said Monday, warning of a high wildfire risk.

The heat "will peak on Wednesday and Thursday," Vassilis Kikilias told reporters ahead of a cross-ministry meeting.

As a result, Greece's fire risk warning will be placed at a "very high" level of four on a scale of five, he said.

Meteorologists had warned that temperatures could hit 43 degrees Celsius this week before falling at the weekend.

Greece had its warmest winter on record, followed by higher-than-normal temperatures in April.

Wildfires, a perennial problem in the Greek summer, started as early as March at an altitude of over 1,000 metres (3,280 feet).

This month, firefighters have battled dozens of forest fires on a daily basis.

"It will be a very difficult fire season," Kikilias said Monday.

Greece has adopted stiffer sentences for accidental and premeditated arson.

From May 1 perpetrators will face up to 20 years in prison and a fine of up to 200,000 euros ($215,000).

According to the National Observatory of Athens, fires in 2023 consumed nearly 175,000 hectares (432,000 acres) of forest and farmland in Greece after a two-week heatwave, the longest on record.

Increased temperatures driven by human-caused fossil-fuel emissions are lengthening fire seasons and causing more land to be burned in some places, according to the Intergovernmental Panel on Climate Change.