Health officials said a woman died at Nicosia General Hospital suffering from heatstroke; another five elderly patients were being treated in hospitals with severe symptoms of heatstroke.

State health organisation spokesperson Charalambos Charilaou told reporters the woman suffered a cardiac arrest twice on arrival at Nicosia's accident and emergency department.

"After investigating the incident, A&E doctors determined that the cardiac arrest was a result of heatstroke," Charilaou said.

He said hospitals have been dealing with cases of heat exhaustion for several days.

On Friday, Cyprus issued its first red alert of the summer for extreme heat, with the Meteorological Department confirming that maximum temperatures reached 45 degrees Celsius.

It was the hottest June day ever recorded on the Mediterranean holiday island.

Due to the extremely high temperatures, the Department of Labour Inspection halted heavy and moderate outdoor work during the afternoon.

Between 12 pm and 4 pm, the transportation or delivery of products using two-wheeled vehicles was also suspended.

Following criticism of the government for not having adequate cooling systems in schools, the education ministry also cut short classes in primary schools, kindergartens and special needs schools at 10:45 am.

Weather experts say that heatwaves of over 40 C are becoming longer in duration.

Friday's record temperature was 10 degrees above the seasonal average for Cyprus.

An early heatwave already gripped Greece earlier this week, prompting authorities there to close the Athens Acropolis and other tourist attractions during the hottest hours of the day. Maximum temperatures in the Greek holiday island of Crete reached 44.5 C.