New York: UN Chief Antonio Guterres will visit Pakistan to take stock of the catastrophic flood situation, the one described by country's Prime Minister Shehbaz Sharif as "the worst in history."

Munir Akram, Permanent Representative of Pakistan to the United Nations in New York in a tweet wrote, "We warmly welcome the Secretary-General @antonioguterres decision to visit Pakistan. This is a demonstration of his solidarity with the people & Govt of Pakistan in this hour of need & his determination to mobilize the entire @UN system to respond to this human catastrophe."

The United Nations issued a flash appeal on Tuesday for USD 160 million to help Pakistan deal with devastating floods that have killed over 1,000 people and affected millions of lives.

"The Pakistani people are facing a monsoon on steroids. More than 1000 people have been killed - with millions more lives shattered," Guterres said in a video message for the launch of the appeal in Islamabad and Geneva. "This colossal crisis requires urgent, collective action to help the Government and people of Pakistan in their hour of need," he added.

Cautioning the world of the imminent repercussions of climate change, the UN Chief wrote, "Let's stop sleepwalking towards the destruction of our planet by climate change. Today, it is Pakistan. Tomorrow, it could be your country."

At least 1,136 people have died while 1,634 have been injured since June 14 from the rains and floods, according to Pakistan's National Disaster Management Authority (NDMA).

It further said that 28 people had died in the previous 24 hours, and authorities were still trying to reach cut-off villages in the mountainous north.

The NDMA said more than two million acres of cultivated crops have been wiped out, 3,457 kilometres (about 2,200 miles) of roads destroyed, and 157 bridges washed away.

Looking at the situation, the Pakistan coalition government, on Monday, approved the establishment of the National Flood Response and Coordination Centre to provide an institutional response to the flood calamity.

"The centre will serve as a bridge between disaster management authorities, donors and government institutions," PM Shehbaz announced on his Twitter handle.

He further added that the centre will collect and analyse the latest information and pass it on to the relevant government agencies. It will also oversee rescue and relief work including restoration of infrastructure.

Pakistan is grappling with its worst natural disaster in over a decade. The floods have affected the lives of millions of people after which the Pakistan government declared a "national emergency".

The NDMA's latest survey shows that 5,773,063 people have been affected by the floods. However, it clarified that the data in today's survey was based on confirmed figures but its estimates showed that more than 33 million of the population has been affected by the floods. The authority shared that 51,275 have been rescued while 498,442 have been moved to relief camps.

According to NDMA, Pakistan's 30-year average showed that it has received 134mm of rain and this year it received 388.7mm of rain. 190.07 per cent more than the average.

As of 25 August, Pakistan has experienced 375.4 mm of rainfall - 2.87 times higher than the national 30-year average of 130.8 mm.

These rains have primarily fallen on Baluchistan, Sindh and parts of Punjab, with Baluchistan receiving five times its average 30-year rainfall and Sindh receiving 5.7 times its 30-year average, the statement reads.