Rehman said 39 of the 77 people died in rain-related incidents just in Baluchistan since last month.
“This is a national disaster,” Rehman said about the rain-related casualties.
TV footage showed some vehicles being swept away by the deluges of floods in Baluchistan.
Heavy rain also lashed Islamabad and the eastern Punjab province.
In a statement, Pakistan’s President Arif Alvi expressed his grief and sorrow over the loss of life in Baluchistan and elsewhere in the country.
Streets and homes were flooded in Quetta, the capital of Baluchistan province, the provincial disaster management agency said.
Rehman the recent rains in Pakistan were 87% heavier than the average downpour.
She linked the new pattern to the changes in climate, saying Pakistan should be ready to face more flooding because the country’s glaciers are melting at a faster pace. That’s causing flash floods that have damaged infrastructure.
Naseer Nasar, a spokesman at the Baluchistan disaster management agency, told The Associated Press that at least 50 people were injured in rain-related incidents in the province since June. He said rescuers were transporting people to safer places away from floods and rain-hit areas in Baluchistan.
Every year, many cities in Pakistan struggle with the annual monsoon deluge, drawing criticism about poor government planning. The season runs from July through September and experts say rains are essential for irrigating crops and replenishing dams and other water reservoirs in Pakistan.
Some of the areas in southern Pakistan have faced drought since earlier this year.