The region has already endured repeated severe flooding in recent months and the Bureau of Meteorology is warning more could be on the way after rain over the weekend.

Minor flood warnings are in place for Wilsons River in Lismore and Richmond River at Coraki and Bungawalbin.

Rain is expected to continue throughout Monday and for the rest of the week.

"There's a chance we could see higher rainfall totals in parts around the coastal fringe and that's going to be particularly as they go across Tuesday, as well as Thursday and Friday," the bureau's senior meteorologist Jordan Notara told AAP.

He said soils in the Northern Rivers region and the northeast of the state remained heavily saturated and had not dried from the deluge of a record-breaking soggy summer, increasing the chances of flash flooding.

Some areas had already had their May average rainfall fall over the past few days, the weather bureau said.

More than 50mm of rain fell in the 24 hours to 9am on Monday in multiple areas of northern NSW, including Lismore and Mullumbimby.

More than 100mm was recorded in the Tweed region at Kingscliff.

Australian Associated Press