At Jim Wild Oysters in Greenwell Point, Sally McLean and her team are preparing for imminent flooding, which is predicted to impact much of the Shoalhaven.

A severe weather warning is active for the region, along with a flood watch for rivers up and down the South Coast.

Significant rain has halted the oyster harvest this week; 50mm in the local area is enough to reduce water quality through runoff and affect salinity.

But with flooding on the way, it is unclear how long the pause on harvest will last.

Ms McLean said their current stocks, combined with a backup plan, will tide them over in the short term.

"The river is closed to harvest at the moment, but we have [previously] pulled a fair bit out, and are keeping them in our cool room and opening fresh daily," she said.

"We should run out probably in the next couple of days, and then I have sourced oysters from Merimbula because they were still open.

"Those will be coming up this week. After that, I don't know what we're going to do because most of the rivers are closed."

It's touch and go for the oyster farmers, as they contend with one adverse weather event after another.

Drought, fires and floods all impact the oyster growing climate in different ways.

In current conditions, changes in salinity and also the large amount of runoff from nearby areas are the biggest concerns, as it can affect the quality and safety of the oyster meat.

At Jim Wild, Ms McLean said they will be watching and waiting for water quality to return after this week's rain and flooding.

"To get the river back open, we have to send in meat tests of the oysters, we test the water, and test for algal blooms," she said.

"We are doing this every seven to ten days."

Once the tests show improvements, it will be all systems go once again.

"We will be closed for quite a while after this big rain event."

There is one light at the end of the tunnel, which is big tides. They are expected to help the estuary bounce back to its optimal salinity.

In the meantime, the oyster farmers are getting on with flood prep, moving equipment to high ground as a precaution.

"There's about 13 farmers that farm here [at Greenwell Point]," Ms McLean said.

"I'm sure they'll all be out preparing, maybe tying things down and getting ready, though hopefully it doesn't happen."

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