New Zealand seafood continues to fetch premium prices at the renowned Sydney Fish Market.

FinestKind owner Donna Wells was there just after dawn on Wednesday to see yellow belly and sand flounder receive top dollar at auction.

To further the provenance of the highly regarded New Zealand product, Donna is placing pictures of the catch vessel on the polystyrene boxes - in this case Port Nelson-based Kiwi.

"Very good product," the Indonesian buyer said on the auction floor.

About 10 percent of the 13,000 tonnes of seafood sold annually at the market, the world's second largest after Tokyo's Tsukiji, comes from New Zealand.

Ngai Tahu blue cod, processed the day before at Bluff, was also snapped up on the day.

Delivery time from New Zealand is usually faster than it is from Australian states.

 

The fish market, founded in 1945, has become a major tourist attraction, as well as the source of Sydney's best and cheapest seafood.

An incredible number of visitors - three million a year - come here.

Well heeled tourists from China arrive by tour bus straight from the airport and spend an average $10-15,000 per group.

It is not hard to rack up such a sum when live Tasmanian king crabs, the world's largest species, sell for $180/kg.

Market guide Alex Stollznow held up a fearsome-looking specimen weighing 9kg, valued at $1600.

The Asian tour groups are also keen on Penfolds' flagship Grange, available at the market bottle store for around $700 a bottle.

Annual seafood sales here total $160 million and combined with tourism provide a major boost to the NSW economy.

Over 100 different species totalling 55 tonnes are sold on an average day under a Dutch auction system originally applied to selling tulips.

Registered buyers, 180 on this day, sit in tiered rows in a grandstand as three auctions proceed simultaneously, each taking only several seconds.

The price is set at $3 to $5 above what is expected and the electronic clock rapidly winds down until a button is pushed and the sale is made.

If the buyer is too eager, he may pay over the odds. But wait too long and there is the risk of missing out. As soon as it becomes profitable to the buyer, the product is sold.

In pre-electronic days when it was a voice auction, 200 boxes would be sold an hour in marathon 14-hour days.

Now the market opens at 3am, the product delivery cut-off is 4am, buyers have 90 minutes to inspect the seafood on offer, the auction begins at 5.30, is all over by about 8.15 and an hour later is all out the door, being delivered to restaurants and retailers across the city and surrounds.

Quality is paramount. An emphasis on delivering the seafood in the best possible condition and widening consumer tastes have seen some marked price increases. An example is live pippies that 10 years ago sold for $5kg as bait and now fetch $30kg as a gourmet food.

All the product is chilled or live, not frozen.

The market employs three assessors to ensure quality is maintained.

It aims to be the world's best on the back of a $250 million redevelopment on a harbourside site next door, due to open in 2021.

The current market, as popular as it is, is cramped and rundown, the site of Fairfax's onetime newsprint warehouse.

The new facility, a dedicated fish market for the first time, will have a wavy roof and solar panel cladding like fish scales.

The market was a popular destination ahead of the Australian industry's biennial Seafood Directions conference in Sydney this week,  where market manager Bryan Skepper detailed the new development to 350 delegates.