Owners of Berry Cool Nursery on Coolangatta Road, Berry said they believe a 'mini tornado' caused the mess, which left twisted metal and other debris jammed into the ground.

The sheds were built to withstand winds of 100km/hr, so the scene came as a shock when the owners woke to the damage on Thursday morning.

"It wrecked two sheds, ripped their rooves off," said Kimmy Therease. "There's twisted metal everywhere."

"It's picked up a roof and taken it over the top of 20 metre pine trees, over the potting shed and landed in the front yard.

"There's metal that's so deep in the ground that we'll need a machine to get it out."

With significant damage to the potting shed, which acts as the "ICU for plants", Kimmy said it would take weeks to repair.

"All the plants are still underneath the collapsed potting shed," she said. "We can't get them until we can pull the shed apart."

"It'll be a couple of weeks before we can even think about rebuilding."

Luckily, no one is injured and the nursery is still open.

Kimmy said while tornadoes are unusual in the region, the series of tornadoes in Kiama in 2013 almost caused damage to the Berry property.

The 2013 tornadoes were triggered by a warm front which developed from a cyclone.

"It missed this property by about 850 metres and the front of the property by 350 metres," she said.

A spokesperson from the Bureau of Meteorology said at this stage, it is unknown what caused the "unusual" weather event on Thursday and said it would unlikely fit the scientific definition of a tornado if other properties in the area weren't damaged.

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