The markets, which are a far cry from what they used to be but remain the only central produce markets outside a capital city in Australia, are home to six wholesale agents that sell to mainly independent grocers across the Hunter and northern NSW.

But at 9.30am every Friday, the markets are opened to the public after wholesalers have fulfilled the needs of their commercial buyers.

Hunter Fresh Produce owner Derek Moodley said the past few days had been flat chat as a result of strong sales at grocery counters throughout the state's north.

Live news updates: The coronavirus crisis in Newcastle and the Hunter

The Newcastle Herald reported on Thursday how small Hunter grocers had been inundated by shoppers searching beyond major urban supermarkets.

Mr Moodley said his business had packed "a full semi-trailer" worth of potatoes for small retail shops on Thursday, more than four times the usual amount.

"It's like the toilet rolls, I don't why," he said. "We've actually got a lot of [potato] supply because of where it's grown and how it's grown.

"But because of the crazy buying, it's put a lot of pressure on the factory. You set up to do X amount of work week-in, week-out, and then all of a sudden you've got to do four times that level.

"It's only a jam in production in getting the product out that's caused it, not because of a lack of supply in potatoes and onions.

"But by people doing what they're doing, it's driving the price up. If it was normal and they went in and bought potatoes like they have for the past 20 years, the price wouldn't go up."

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General customers on Friday rushed in to get what they could. While it was a standard sized crowd, some were not able to get what they wanted or had to pay more.

Jason, who has visited the markets regularly for the past four years to get "staple items", said "there was less produce on the floor" and an "increase on some prices".

"In some cases there's a 100 per cent increase on the wholesale prices today, and that's right across the board," he said. "I couldn't get tomatoes, eggs and I wasn't able to get the amount of potatoes I usually get.

"Obviously if the retailers are buying more produce, there's going to be less for the public to access at the end of the week. But that's the market and how things go."

Jason said he would usually pay fifty cents a kilo for carrots, but they were selling for $2 a kilo.

He found onions were selling for $2 a kilo, but said they were usually between fifty cents and $1 per kilo. Even eggs were up to $8 per tray, from $6, he said.

Mr Moodley said costs had risen along the supply chain as a result of the increased demand for food amid the coronavirus outbreak.

"We sell here on behalf of our growers," the 58-year-old, who used to run a fruit and veg store in Georgetown, said. "They know what volume of product we have to have to keep operating ... but you multiply that by four overnight, and they've got to find staff to harvest.

"But where do you find staff because all the other farms are having the same issues, and then you move that down the line and you're looking for trucks.

"You've got to find maybe three, four extra trucks to transport the gear."

John Garret, the fifth-generation of his family to run wholesale business T. Garrett and Sons, said some produce was already in short supply from the impact of drought.

"With the different growing seasons they've got in whatever areas [produce] is coming from, if their crops have been in a drought situation the crops probably aren't producing as much as they should be," he said.

"A lot of crops probably haven't set as well as they should have and therefore supply becomes limited."

Mr Garret, 56, mainly deals in fruit and said apples "were not in limited supply, but volumes are down".

"A lot of our apples are coming out of Shepparton and Batlow, and Batlow copped it big time with the fires so their production is way down," he said.

Mr Moodley agreed the drought had caused some produce to be in short supply and more expensive.

"Products are drought affected," he said.

"They didn't plant as much because they were buying water, and it's been expensive to buy water. A lot of vegetables come from Victoria, and the 40 to 45 degree heat didn't help. That caused a lower production as well.

"By probably mid next week, things will settle down a bit. Prices are not going to come back in a big way, because supplies are still short. You can't just plant overnight."

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