KARACHI: Pakistani disaster relief officials issued fresh flood warnings Sunday after the death toll from heavy monsoon rains rose to at least 45 and waters paralysed parts of the largest city Karachi.

Flash floods caused by monsoon downpours have inundated some main roads in the sprawling port city and swept away homes in the northwestern province of Khyber Pakhtunkhwa.

According to the Provincial Disaster Management Authority, the death toll in Chitral is seven, with 60 homes damaged and 120 partially damaged. Deputy Commissioner Chitral, Shoaib Jadoon said that the power to Upper Chitral was disconnected and Boni Reshun, Mastuj, Garam Chasma have been the worst hit.

Deputy Commissioner Peshawar, Zaheer Islam confirmed that four people were killed in the city. Cooked food was being provided to the affected people and dewatering machines were installed to pump out water from houses on Charsadda Road and other flood hit areas.

Five people were confirmed dead in Tank, while 30 homes were left damaged in Ali Khel and 14 in Darakai. Four people lost their lives in Central Kurram, two in Khyber Agency, and one in Lakki Marwat.

More than 300 homes have been swept away or destroyed in a tehsil in Dera Ismail Khan by torrential waters which poured from the Gomal River and heavy rains in South Waziristan.

The National Disaster Management Authority warned that more thunderstorms and heavy rains were expected on Monday across the country and some rivers may flood.

At least 45 people have been killed in the floods over the weekend.

Officials in Karachi said at least 19 had died in the city to add to 20 dead in the northwest and six in the southwestern province of Balochistan.

Doctor Semi Jamali at the Jinnah Hospital in Karachi told AFP that most of the deaths occurred due to electrocution or collapsing roofs and walls.

Army engineers helped relief efforts in Karachi on Sunday where roads and streets were flooded and the city was practically paralysed, an AFP reporter said.

Authorities in the city of 18 million people, which contributes 42 per cent of Pakistan's GDP, said it would take more than two days to clear up after the water flooded markets, buildings and houses and blocked roads.

Hundreds of cars were seen half-submerged after poor sewerage and drainage systems choked due to garbage.

Prime Minister Nawaz Sharif sent three of his cabinet ministers to inspect damage in flood-hit areas in Sindh, Khyber Pakthunkhwa and Balochisan and suggest measures needed to bring the situation under control.

"The president advised the federal and provincial government departments to take every possible step for providing relief to the rain-hit people and evacuating those stranded in water," President's Spokesman Senator Farhatullah Babar said.

Mr Zardari said the affected people should be moved to safe places immediately and tents, rations, drinking water and other basic necessities provided to them.

The president also instructed the authorities concerned to ensure there was no outbreak of water-borne diseases in the affected areas. He said medical camps should be set up for the affected people.

Floods in Balochistan leave more than 20,000 homeless: officials‏

Meanwhile, Attaullah Mengal, the Director Provincial Disaster Management Authority (PDMA) told Dawn.com that torrential rains and flash-floods left more than 20,000 people displaced in Jhal Magsi, Lorlai district and other parts of Balochistan.

He said road connection between Jhal Magsi and other parts of Balochistan was suspended as floods had washed away roads.

"Eleven trucks loaded with relief goods are still stranded at Notal area of Naseerabad," Mengal said.

He said efforts were on to re-open highways to ensure timely provision of relief goods to floods affected people.

Secretary information Balochistan, Qamar Masood told Dawn.com that 27 villages were inundated in Jhal Magsi district of Balochistan.

He said flood water has also entered into police line, civil hospital, live stock office and other official buildings in Gandawah.

"Floods have severely affected functions of government departments," Masood said.

He said three people including two children and a woman were killed when the roof of a house collapsed in Naal tehsil of district Khuzdar.

He said torrential rains have damaged dozens of mud-walled houses in different parts of Naal and Khuzdar district. He said one person was killed in Jhal Magsi and one in Loralai were killed in floods related incidents.

More than two dozen mud-walled houses were collapsed as result of torrential rain in Nawan Killi area of Quetta. More than two hundred women, children and aged people were displaced as result of collapsed houses.

Attaullah Mengal however said tents were dispatched in Nawan Killi to provide shelter to affected people. However, affected people were complaining that they had not received any aid on the part of officials.

Pakistan has suffered devastating monsoon floods for the last three years, including the worst in its history in 2010 when catastrophic inundations killed almost 1,800 people and affected 21 million.

With additional reporting by Zahir Shah Sherazi in Peshawar and Syed Ali Shah in Quetta.