Christmas may bring floods to NSW | Coffs Coast Weather | Local Weather Forecast for Coffs Coast

AAP

SOME of the heaviest rain in a decade is expected in parts of NSW on Christmas Day, with residents urged to stockpile food and prepare for severe flooding.

Forecasters at the Bureau of Meteorology (BoM) on Wednesday issued an alert about a developing weather system, formerly known as Tropical Cyclone Laurence.

The system is expected to track across the continent and become slow moving near the Queensland-NSW border on Christmas Day.

"This event could bring the heaviest widespread rainfall to northern inland NSW for over a decade," BoM NSW regional director Barry Hanstrum said in a statement.

BoM's regional hydrology manager Gordon McKay said the effects could be felt through to the state's far west.

"If predicted rainfall totals of 200-300mm eventuate, there could be major flooding in many areas including Gilgandra, Coonamble, Bourke and Nyngan," he said.

"Our main concern is flooding along the Castlereagh, Bogan, Lower Namoi and Lower Macquarie rivers, and a Flood Watch has been issued.

"It's too early to pin down exactly where the worst flooding will be, but I urge people to maintain a close watch on the latest forecasts and warnings from the Bureau of Meteorology."

NSW State Emergency Service (SES) Commissioner Murray Kear said he had been working with the BoM to plan and prepare support for the affected communities.

"Rural property owners in the affected areas should ensure that they have sufficient food, fuel and medicine to last five to seven days," Mr Kear said.

Livestock should be relocated to high ground where they can be provided with feed for the duration of any flooding.

Farm equipment and pumps should also be relocated to higher ground.

"Rain may make unsealed roads impassable and causeways may be covered in fast flowing floodwaters," Mr Kear said.

"The SES urges that people never drive, ride, walk or play in floodwaters as water may be deeper or faster flowing than it looks and contain hidden snags and debris."