The Bureau of Meteorology has issued a severe thunderstorm warning for heavy rainfall for the Northern Rivers.

The heavy rainfall is likely to produce intense rainfall that may lead to dangerous and life-threatening flash flooding in the warning area over the next several hours. Locations which maybe affected include Lismore, Ballina, Casino, Kyogle, Yamba and Maclean.

A line of storms embedded within a slow moving rain band is generating heavy rainfall for parts of the Northern Rivers.

Be aware that run-off from rainfall in fire affected areas may behave differently and be more rapid. It may also contain debris such as ash, soil, trees and rocks.

Trees that have been damaged by fire are likely to be more unstable and more likely to fall.

Stay vigilant and monitor conditions. Note that the landscape may have changed following bushfires.

Clothiers Creek recorded 78mm and Tumbulgum recorded 68mm in 60min from 4:45am to 5:45am.

A heads up if you were thinking of travelling to the Gold Coast or Brisbane today. The M1 has been closed in both directions in Helensvale after more than 300mm was recorded on the Gold Coast.

The State Emergency Service advises that people should:

* Keep clear of creeks and storm drains.

* Don't walk, ride your bike or drive through flood water.

* If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.

* Unplug computers and appliances.

* Avoid using the phone during the storm.

* Stay indoors away from windows, and keep children and pets indoors as well.

* For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.