The storm also toppled a number of trees, while power lines were brought down.

A 24-year-old Settlement Point Road woman was injured when the roof of a home was torn off. NSW Ambulance attended but the woman was transported to Port Macquarie Base Hospital in a private vehicle.

Her condition is listed as stable. She is expected to be discharged from hospital later this evening.

Rural Fire Service crews from the North Shore and Lake Innes brigades along with SES volunteers attended the scene. Fire and Rescue NSW crews concentrated their efforts on the Settlement Point Road community.

Some 335 homes on North Shore and a further 118 homes on Settlement Point Drive were without power. Bellangry residents were also without power, according to the Essential Energy website.

It is believed that power will remain out in some areas - particularly on the North Shore - for up to 24 hours.

RFS North Shore brigade captain Kingsley Searle said the mini tornado lasted just 20 minutes.

"But there was about 25mm of rain in that time and it has just ripped through both (North Shore) communities," he said.

"I've never seen anything like it in all my time here.

"Some homes have had their roofs just peeled off and thrown across the road.

"We are heading across the river to pick up more tarps. I think it is going to be a long night ahead."

A section of roadway on Riverside Drive will also require repairs after a tree was brought down causing some damage to the road surface.

According to the SES, the Bureau of Meteorology is predicting that slow moving thunderstorms across the Northern Rivers and Mid North Coast may bring heavy localised rainfall and possible flash flooding.

With the possibility of wet and stormy weather on the way, NSW SES Acting Deputy Zone Commander Maria Frazer urged residents to prepare their properties and to monitor severe weather warnings.

"Bring in or secure any outdoor items in the yard or on the balcony, check your gutters are clear and your roof is in good condition, trim any overhanging branches and take care when travelling in poor weather conditions."

"With this approaching system the current chance of riverine flooding is low at this stage, with our main focus being on potential storm damage to properties and flash flooding."

NSW SES urges residents and visitors to take care when driving in wet weather on the local roads and especially if you are driving in upper catchment areas where low lying rural causeways can overflow and are dangerous to cross when flooded.

NSW SES reminds people to never drive, ride or walk through floodwater as this is the main cause of death during floods.

NSW SES volunteers on the Mid North Coast have been very busy over the last month responding to 228 requests for storm assistance with the hardest hit areas being Cundletown, Wingham, Port Macquarie, Taree and Macksville.

The NSW SES and Bureau of Meteorology are continuing to monitor the weather system closely. Stay alert this week, listen to any updates and advice and monitor the Bureau of Meteorology website on www.bom.gov.au .