Sydney -- More than 4,000 people were isolated by flood waters and as many as 1,800 have been evacuated in the Australian state of New South Wales after a week of heavy rains, the government said Monday.

As a result of this week's rains, the government has so far issued disaster declarations in 17 of the state's rural and suburban districts, predominantly in the south and west. They join 17 other districts declared disaster areas after flooding in October.

The flooding, which is expected to continue as a new storm front is forecast to bring extended heavy rains through Friday, has already destroyed an estimated $500 million in crops in the region, according to a statement issued by New South Wales Emergency Services.

The hardest-hit communities include Wagga Wagga and Coonamble, both located in the southern part of North South Wales, which is located in Australia's southeast.

The community of North Wagga Wagga was completely isolated on Monday, the emergency services agency said.

Some evacuated residents of Eastern Coonamble have been allowed to return to their homes, although the government warned further flooding expected from the rains forecast for later this week could renew the danger.

Flood warnings remained in effect Monday for communities along 13 rivers in New South Wales, including Castlereagh River, MacQuarie River and Murrumbidgee River.

The Australian Bureau of Meteorology issued a flood watch Monday for northwest, southwest and central New South Wales, warning that another significant storm approaching the region could cause additional flooding.

Since the most recent flooding began Nov. 29, emergency workers have executed 67 flood rescues and received more than 1,300 requests for assistance, the emergency services agency said. Most of the requests involved damage caused by flash flooding.