New flooding in Pakistan sent 150,000 people to higher ground Saturday as aid agencies struggled to help the millions of people already affected by the disaster.

The evacuation of homes was carried out in southern Sindh province as the latest surge approached. Already, 600,000 people are in relief camps set up in Sindh province because of flooding over the past month.

Howard Arfin, spokesman for the Canadian Red Cross, is in one of the worst affected areas.

"We're seeing first-hand the massive destruction from a river that is five times its normal size. Homes are washed out all around us. We're still seeing people up to their chests in water," he told CBC News.

"To some extent, the waters in the north are subsiding and we're hoping that a second round of monsoon rains don't increase the misery.

"Of course, this great wall of water is moving southward into the southern provinces and causing further inundation there," he said.

According to Arfin, six million people are already homeless, and there are upwards of 20 million people whose lives have been impacted.

The floods began in the northwest, hitting the Swat Valley and areas close to the main city of Peshawar, before moving down the country by way of the River Indus, devastating millions of hectares of crops in the country's "breadbasket" in Punjab and the Sindh.

About one-fifth of the country — a chunk of land about the size of Italy — has been affected.

At least eight million people are in need of water, shelter or other emergency assistance, making the disaster larger than Pakistan's last two humanitarian crises: The exodus from Swat last year, amid an army offensive against the Taliban, and the 2005 Kashmir earthquake.

The floodwaters now covering roughly 6.8 million hectares are blamed for killing about 1,600 people.

On Friday, the United Nations said it has raised about 70 per cent of the $460 million US it called for in its emergency appeal.