At least 63 more people died on Sunday from the effects of Pakistan's record-breaking heat wave, bringing the weekend death toll to 110, news reports said on Monday.

The mercury rose as high as 52 degrees in south-west parts of the country as the hot spell entered its fourth day, also setting a 78-year record in the city of Lahore in the central Punjab province.

About 50 people died in the province, where the temperature hovered around 49 degrees and prolonged power cuts added to the discomfort, the newspaper The Nation reported on Monday.

Hundreds of people were also hospitalised with sunstroke, newspapers reported, while meteorologists predicted the heat wave will last at least three more days.

Thousands of people from the plains of Punjab headed towards the northern mountain regions to find relief, many of them to Murree, a hill station and traditional summer resort located 2 300 metres above sea level.

A similar heat wave killed more than 80 in Pakistan last year.