Heavy rain intensifying on NSW north coast

A severe weather system is expected to deliver as much as 200mm of rain and trigger flash flooding in northern NSW.

Heavy rain and flash flooding are predicted on the north coast of NSW. Source: AAP

Heavy rain and thunderstorms are forecast for parts of the northern NSW coastline, with 200mm of rain expected to bring flash flooding.

A severe weather warning updated by the Bureau of Meteorology on Saturday evening placed communities on the state's mid north coast and northern rivers on flood alert.

The bureau says Lismore, Grafton, Coffs Harbour, Port Macquarie, Sawtell and Dorrigo may be affected.

Evans Head and Yamba had already copped more than 130mm of rain in the 36 hours since Friday morning.

People in affected areas have been advised to avoid driving or walking through floodwater and to keep clear of creeks and storm drains.

Evans Head and Yamba each received 133mm in the 24 hours to 9am on Saturday morning, while Tuckombil received 98mm.

A severe weather warning for the Hunter region has been cancelled.