At least 78 people have died and dozens more injured in torrential rains and flash floods that have wreaked havoc in Pakistan over the past three days, a government spokesman said Monday.

Heavy monsoon rains which began falling last week have destroyed more than 1,600 houses and damaged a further 5,000, Irshad Bhatti, a spokesman for the country's National Disaster Management Authority (NDMA) told AFP.

"A total of 78 people have died and 68 injured in rains and flash floods in the country so far," he said, adding that the casualties were caused mostly by houses collapsing and people being caught in floods.

The worst-hit region was Khyber Pakhtunkhwa province where 32 people have died and 26 injured in several districts, he said, adding that 83 houses were totally destroyed and another 4,200 were partially damaged.

In the northwestern district of Swabi eight Afghan refugees were killed when the roof of their mud house collapsed overnight, police official Mohammad Ali said.

The dead, who were members of the same family, included two women and six children aged between one and 12 years he said.

In Pakistan-administered Kashmir flash floods killed at least 31 people, Bhatti said, just a month after heavy rains led to the deaths of at least 26 people in the same region.

At least four people were killed in central Punjab province where more than 200 houses were damaged, officials said.

Details were not given for where the other deaths occurred but the toll was expected to rise considerably with unconfirmed reports of more than 30 killed in Sindh province.

"The provincial government has declared an emergency in Jacobabad, Khairpur, Kashmore districts which have been badly affected by the rains," Haleem Shaikh, advisor to the Sindh government said.

"Hundreds of people have been displaced so far, we fear for many more people going homeless as the rains are still incessant in those districts."

A state of emergency has also been declared in the Dera Ghazi Khan and Rajanpur districts of the Punjab province, where army troops have been called to join rescue work, local administration officials aid.

Expressing "deep concern" over the havoc caused across the country by the recent rains, President Asif Ali Zardari has directed national and provincial disaster management authorities to gear up their efforts in providing relief to the affected people.

Weather officials predict heavy rain in the next two days in southern Sindh and Baluchistan provinces and rescue teams are closely monitoring the situation, Bhatti said.

"It is not comparable to what we saw last year. We hope the current spell will end over the next two days and water will start receding in affected areas," he said.

Last summer's floods killed more than 340 people and affected almost six million, killing livestock, destroying crops, homes and infrastructure as the nation struggled to recover from record inundations the previous year.

In 2010, unprecedented monsoon rainfall triggered catastrophic flooding across the country, killing almost 1800 people and affecting 21 million..