Minister for Climate Change Sherry Rehman said that the current monsoon rains have claimed 77 lives, with Balochistan reporting the most number of deaths.
Addressing a news conference in Islamabad on Wednesday, she said that Balochistan has reported 39 deaths so far.
She added that the toll was taken from June 14, when the monsoon started.
"For me, it's a national tragedy. When people die like that, it's not a small thing ... it is just the beginning. We have to prepare for it."
Monsoon rains likely to continue until 7th
The minister said that the National Disaster Management Authority (NDMA) has prepared a national monsoon contingency plan, adding that provinces, districts and citizens have to stay alert to reduce casualties.
Meanwhile, the Balochistan government declared an emergency in Quetta district. As per the Balochistan Disaster Management Authority, Qila Saifullah, Zhob, Pishin and Harnai districts have been the most affected by the rains, it was reported.
Authorities have been placed on high alert as the Pakistan Meteorological Department forecasts more rain in the next three days. The Army and Frontier Constabulary have also been put on high alert to deal with emergency situations.
The monsoon, which usually lasts from June to September, is essential for irrigating crops and replenishing lakes and dams across the Indian subcontinent, but each year also brings a wave of destruction.
Poorly built homes across Pakistan, particularly in rural areas, are especially prone to collapse in floods, which also destroy huge tracts of prime farmland.
The worst floods of recent times were in 2010 -- covering almost a fifth of the country's landmass -- killing nearly 2,000 people and displacing 20 million.
Pakistan is the eighth most vulnerable country to extreme weather caused by climate change, according to the Global Climate Risk Index compiled by environmental NGO Germanwatch.
"One day you have drought and next morning you are expecting flash flood... so you can see how serious the situation is in Pakistan," Rehman said.