Sydney Fish Market braces for 36-hour rush

A 36-hour shopping marathon will begin at Sydney's Fish Markets ahead of Christmas.

The 36-hour marathon at Sydney Fish Market is proof Aussies don't skimp on their shrimp.

The largest fish market in the southern hemisphere is expecting to sell 130 tonnes of prawns and 900,000 oysters in the two days leading up to Christmas.

Through Wednesday and Thursday, wholesalers, fishmongers, restaurant owners and families will converge on the inner-city fish market to source their Christmas menu.

"It's going to be crazy," said business owner Con Doukas early on Wednesday.

"It's already starting to get busy and it's going to get busier by the hour."

Mr Doukas started preparing months ago and has extra staff and food to cater for the extra customers.

"Prawns and oysters have got to be the most popular ones," he said.

Sydney Fish Market spokeswoman Stephanie Williams said fishermen work extra hard this time of year.

"We anticipate that 660 tonnes of food is sold across the site during the 36 hours," she said.

More than half of Australians will eat prawns this Christmas, according to retail management giant Vicinity Centres.

Sixteen million prawns are to be gobbled down by 13.6 million people from December 24-26.