Pakistan's largest charity, the Edhi Foundation, on Friday urged the government to lift a years-old ban on a number of international non-governmental organisations so they can help with relief efforts following catastrophic floods.

Record monsoon rains and melting glaciers in northern mountains have brought floods that have killed at least 1,208 people, destroyed infrastructure and inundated 2 million acres of agricultural lands.

"I appeal to the government to immediately lift ban on the international NGOs for one year so they could help people," Faisal Edhi, chief of the Edhi Foundation, told reporters on Friday.

Pakistan began a crackdown on international NGOs almost a decade ago, accusing them of "anti-state activities" in Pakistan. By 2018, a number of them had officially been asked to leave on the basis of new and stricter laws.

Eidhi said they should be allowed to return.

International NGOs were active on the ground when Pakistan was hit by floods in 2010 and a devastating earthquake in 2005 and played an important role in relief and rehabilitation work.

The government is struggling to respond to the current floods given their unprecedented magnitude.

Edhi, who returned to the port city of Karachi after spending nine days in the flood-hit areas, described the situation as grim.

"The situation is very bad, and it seems it will worsen. People's participation in providing relief cannot be not seen as witnessed in the 2010 floods and 2005 earthquake," he said.

He said despite efforts, 90% of those affected had not been reached. Pakistan's government has said 33 million people - 15% of its population - have been affected.

One the highest profile NGOs banned and expelled was Save The Children, who the government linked to a Pakistani doctor recruited by the CIA to help in the hunt that led to the killing of Osama bin Laden in Abbottabad.

Save the Children, which had been operating in Pakistan for 35 years, denied any involvement.

Over one-third of those killed in the current floods are children, 416 of whom have been confirmed to have died. The United Natios has warned that more children could die in a matter of days.