NSW Premier Nathan Rees, in Canberra for the Council of Australian Governments (COAG) meeting there, was interviewed late on Saturday.

He told reporters, "A total of 150mm of rain over the last 24 hours in an area that's been drought stricken for some time - that's the dual-edged sword that rural Australia is so used to."

Good rain at the end of spring in this region normally has the potential to boost summer crops. But the flooding and heavy rain has been so severe the region has been declared a disaster area, with some summer crops likely to be lost in the flooding and with damage to late-harvested wheat.

Rapidly-rising floodwaters cut the town in two, with the Peel River reaching its peak around 9am (AEDT) Saturday.

Tamworth airport recorded 164mm of rain in the 24 hours to 9am Saturday.

To the west, the Gunnedah farming district received falls of 110mm-plus.

The attached Bureau of Meteorology (BOM) rainfall map shows the widespread late spring rainfall in the eastern states. It also shows the WA rain, which was accompanied by heavy hail in some areas, damaging wheat still being harvested.

BOM says current warm sea surface temperatures off the north-east coast of Australia and in the Timor Sea in the far north-west of WA, have contributed to the November rain.

This unusually warm water off the coast has resulted in masses of moisture being lifted into the atmosphere, where it feeds into the troughs as they pass through, contributing to the widespread heavy rain.

Also contributing to the increased likelihood of late spring and summer rains, the southern oscillation index (SOI) remains strongly positive.

It finished this week at +16.7 for the 30-day moving average (see graph).

Such a consistently high SOI index usually indicates above-average rainfall in the months ahead for wide parts of eastern Australia.

The bureau reports that the Tamworth rain eased during Saturday, with drier air from the south moving into north-west NSW replacing the moist air.