SOME Tweed residents have started panic buying in anticipation of being cut off by floodwaters and unable to access food supplies.

Bilambil Heights Top Shop owner Kathy Tulk said the flow of customers hadn't stopped all morning.

"We can't get out Kennedy Dr and we can't get over to Murwillumbah," Ms Tulk said.

"We're high and dry but they're panic buying."

General stores across the Tweed Shire have become saviours for residents fearing they'll be isolated by floodwater in the coming days.

Crabbes Creek General Store owner Alan Vincent said the town was completely cut off by rain and people had began stocking up their supplies.

"The road in front of the school is starting to flood and soon everyone in Crabbes Creek will be cut off," Mr Vincent said.

"Most of our residents got prepared yesterday, buying water and extra supplies, cartons of beer.

"This happens a couple of times a year so people know how to get prepared."

Burringbar General Store and Post Office staff member Beris Togo said it wouldn't be long before Burringbar became completely isolated and residents had begun coming in, mostly to get information.

"A lot of people are coming in telling us where it's flooded and where they still have access, many of them just want to know what's going on," Ms Togo said.

She said the Mobil Service Station was almost flooding, that Upper Burringbar was now isolated and Yelgun was also suffering flooding.

"People are starting to get cut off, especially the causeways are going under.

"They're coming in for extra bread and milk."

Pottsville IGA is also bracing for an influx of customers with access to the Pacific Highway along Pottsville and Cudgera Creek Rds about to close.

Stores in both Chillingham and Tyalgum were unable to be contacted with Telstra reporting fixed phone lines and ADSL broadband had been down in those areas since 9.30pm last night.