A short, violent storm in on the New South Wales mid-north coast has damaged more than 50 homes, with the roof completely ripped off one of them.

Key points: The storm has left oyster growers on the Hastings River assessing damage with one grower saying at least 20,000 oysters were unaccounted for

The storm has left oyster growers on the Hastings River assessing damage with one grower saying at least 20,000 oysters were unaccounted for Those damaged in the violent storm are racing to secure damaged roofs damaged ahead of more rain predicted for later in the week

Those damaged in the violent storm are racing to secure damaged roofs damaged ahead of more rain predicted for later in the week A very slow moving high pressure system developing over the Tasman Sea could enhance rainfall in some areas

Emergency services received some 50 calls for help around Port Macquarie's Settlement Point and North Shore areas after what was described as a "mini cyclone".

The damage to Isabelle Poole's home in Settlement Point was by far the worst.

"It started flooding, the water was hitting the sliding doors, then it's just pouring through the house upstairs and downstairs … and then after that the roof came off," she said.

One of the houses in the path of what's being described by some locals as a "mini cyclone". ( ABC News: Luisa Rubbo )

"I could just see the sky, there was nothing there.

"It's horrible, I don't have words. I'm in shock still, I think, it hasn't really sunk in yet."

Her sister's arms and legs were badly cut by glass.

"She was in the dining room when it happened, and when the walls came in she got thrown into the kitchen," Ms Poole said.

"She just had cuts all over her arms and legs and she's got 30 staples and she's got stitches everywhere.

"She's in a lot of pain but she'll survive."

Ms Poole said as soon as it started it was over.

"It was so quick and it was just so full on. The whole thing with the house happened within like four minutes," she said.

A house on Port Macquarie's North Shore was extensively damaged by the storm. ( ABC News: Luisa Rubbo )

Despite the damage, some parts of the home remain untouched.

"In the kitchen, the dishes that mum did yesterday morning are still sitting there, perfect, and there's a tomato sauce bottle on the kitchen bench," Ms Poole said.

Some items in Ms Poole's house didn't move in the violent storm despite tearing the roof off. ( ABC News: Luisa Rubbo )

Barney Bailey watched the storm as it came towards him.

"I was on the veranda watching the storm come and I raced inside and I had to put my shoulder into the door to shut it," he said.

"It was like a cyclone, a mini cyclone. I doubt whether a human standing out there would stand up."

He lost tiles off his roof and is not yet sure how bad the water damage inside his property will be.

Oyster farmers hard hit too

The storm has left oyster growers on the Hastings River assessing the damage they have suffered with one grower describing it as leaving a "big hole" financially.

A number of oyster leases on the Hastings River in Port Macquarie suffered infrastructure losses as a result of the storm. ( ABC News: Michael Cavanagh )

Holiday Coast Oysters managing director Bronwyn Mitchell was on the water at the height of the storm trying to rescue the lines of oyster baskets which had broken free at the height of the tempest.

The morning after, at least 20,000 oysters were unaccounted for.

"I hope that they don't get washed right out to sea," she said.

Local weather forecast Check the current and seven-day forecast, temperatures and warnings for your town on the ABC Mid North Coast weather page.

"With the incoming tides they get washed back in to the estuary and end up in the mangroves and swamps.

"It's then hard work getting anything out of there."

Holiday Coast Oyster is just one of 18 farmers operating on the river.

"Devastating is not the right word, but it is a significant amount of money when you look at the potential market value," she said.

"It also affects availability for the season you are planning for."

Trees were uprooted and power was cut in a short but intense storm in Port Macquarie. ( ABC News: Luisa Rubbo )

While several of the waterways branching off the main body of water were unaffected, about 75 per cent of the oysters grown are in what is known as Big Bay in the main part of the river.

Port Oyster Company owner Paul Wilson spent much of Tuesday morning out on his punt checking his dozen or so leases and those adjoining on Big Bay.

"The damage is fairly extensive. Some leases more than others appear to have borne the brunt of the storm," he said.

"Fortunately some of the lines which broke loose are contained within the leases.

"Some pontoons have broken loose and floated over to other leases causing damage."

The work to repair the infrastructure and recover the baskets full of oysters comes as demand for the product traditionally increases.

More rain on the way

The race is on now to secure roofs damaged by the storm ahead of rain predicted for later in the week.

"What we're going to see is a very slow moving pattern with a high pressure system developing over the Tasman Sea and then remain there for several days," Bureau of Meteorology duty forecaster Jake Phillips said.

"Firstly, what that's going to do is start driving onshore winds onto the NSW coast so that'll bring some showers, but then we're expecting a trough to develop within that onshore wind flow probably during Wednesday and Thursday.

"That looks like enhancing the rainfall in some areas.

"It's a little bit early to pinpoint exactly where, but it's looking more favourable for the northern half of the coast."