Historic monsoon rains and flooding in Pakistan have affected nearly 30 million people over the last few weeks, the country's climate change minister said on Thursday, calling the situation a "climate-induced humanitarian disaster of epic proportions."

The Pakistani government has declared the flood situation in the country a "national emergency" and urged the international community to help with relief efforts as it struggles to cope with the aftermath of torrential rains that have triggered massive floods since last month, killing more than 900 people.

"33 million have been affected, in different ways; the final homeless figure is being assessed," Climate Change Minister Sherry Rehman told Reuters in a text message.

She added that the southern province of Sindh, hardest hit in the last few days, had requested one million tents for affected people.

"South of Pakistan is inundated almost underwater ... people are going to higher ground," she said.

"Needs assessment is being done, we have to make U.N.'s international flash appeal; this is not the task of one country or one province, it is a climate-induced disaster."  

Since mid-June, when the monsoon began, over 3,000 kilometers of road, 130 bridges and 495,000 homes have been damaged, according to the NDMA's last situation report, figures also echoed in the OHCA report.

OCHA also warned that alerts had been issued for floods, river overflows and landslides in several areas of Pakistan, and heavy rainfall was forecast for the next two days over most of the country.

The vast majority of damage is in the southern province of Sindh.

(With input from Reuters)