At least 41 people have died in storm-related incidents across Pakistan since Friday, including 28 killed by lightning, officials said on Monday.

Pakistan's National Disaster Management Authority (NDMA) has warned of landslides and flash floods because more rain is expected in coming days.

Punjab, Pakistan's largest and most populous province, witnessed the highest death toll, with 21 people killed by lightning between Friday and Sunday.

"I have asked the NDMA to coordinate with the provinces... and for the NDMA to provide relief goods to areas where damages occurred," Prime Minister Shehbaz Sharif said on Monday.

People living in open, rural areas are more at risk of being struck by lightning during thunderstorms.

At least eight people were killed in Balochistan province, including seven struck by lightning, where 25 districts were battered by rain and some areas were flooded.

Schools in the province were ordered shut on Monday and Tuesday, delaying the return of students after Eid al-Fitr holidays at the end of the holy fasting month of Ramadan.

Four people were killed in road accidents linked to flooded roads in southern Sindh province.

Another eight people were killed in the northwestern province of Khyber Pakhtunkhwa, including four children, when houses collapsed in the heavy downpours.

Pakistan Peoples Party chairman Bilawal Bhutto Zardari, speaking to local media, blamed climate change for the surge in lightning incidents.

Pakistan is increasingly vulnerable to unpredictable weather patterns, as well as often destructive monsoon rains that usually arrive in July.