But Prime Minister Tony Abbott has moved to reassure the community over the food scare, telling parliament that frozen berries linked to cases of hepatitis A were no longer "entering the food supply chain".

Mr Abbott said Patties Foods berries connected to the outbreak were being "100 per cent screened" and that the federal government and authorities considered the incident a very serious issue.

"Frozen berries linked to cases of hepatitis A are no longer entering the food supply chain," he said.

In response to a question from Greens senator Rachel Siewert at a federal parliamentary hearing, the secretary of the Agriculture Department, Dr Paul Grimes, confirmed that the broader regime of surveillance of imported berries had not changed.

"We have not made changes on surveillance rates for berries broadly at this stage," Dr Grimes told the senate estimates hearing.

Senator Siewert expressed frustration and anger in response to the comments. "It is completely ludicrous that our regulatory body that is supposed to ensure sufficient biosecurity has not increased surveillance on berries since this scandal came to light," she said.

"Whilst Australians continue to contract hepatitis A, it is concerning to know that there is no increased surveillance monitoring these berries as they enter the country. The current regime failed in preventing the contaminated product entering the country in the first place, the Government is not moving quickly enough to prevent further potential infection," she said.

But Dr Grimes defended the Department of Agriculture's response to the food safety scare, which is now in its second week.

"In relation to the product that is linked to hepatitis A, we have taken firm and decisive action."

There are 18 hepatitis A cases linked to the suspect Patties Foods berries in four states, including seven in Queensland and seven in New South Wales. The virus, which affects the liver, takes up to seven weeks to incubate and the outbreak is expected to grow.

The Agriculture Department said the Chinese Government had inspected the packing facilities implicated in the outbreak and taken swabs for microbiological testing.

The department had also "interrogated" Australia's main system for managing imports, the Integrated Cargo System, and begun surveying all known importers of frozen berries from China.

The frozen berries category had been rapidly growing, driven by popularity of at-home fruit smoothies, said Euromonitor research analyst Daniel Grimsey. But now customers are turning to the fresh variety.

Frozen berry sales at Harris Farm stores have been hit hard by the disease outbreak. Fresh berry sales are stable.

"We have three lines of frozen berries from New Zealand and Chile not affected by the recall and sales have gone to zero," said co-chief executive Tristan Harris. "People have clearly been spooked."

Grocery retailer Coles, which stocks private label frozen foreign berries, said demand for fresh berries was "solid" and, because it was peak season, supply was plentiful.

In the past week, online grocer Aussie Farmers Direct's sales of $5.99 blueberry punnets had jumped 40 per cent, and its sales of $4.49 strawberry punnets had jumped 215 per cent, buoyed by a "two for $5" deal  at the weekend.

Prices for the Victoria and Queensland-sourced berries are the same now as they were before the health scare.

"I can only speak for our business, but I can categorically tell you we are not increasing prices because of an issue like this," said chief executive Keith Louie, who hopes the renewed interest in locally-grown food will continue.

It is boom time for Australia's berry growers. They say consumers are willing to pay the premium for fresh product.

Last week, Leo's Fine Food and Wine replaced imported frozen raspberries with Tasmanian-grown ones. Farmer Richard Clark's berries are priced at $7.95 for 280 grams - 42 per cent more than the Creative Gourmet variety.

All 24 units from the first order were sold out in two days without any marketing.

At the end of every six rows of raspberry canes at Mr Clark's property are bottles of alcohol sanitiser, similar to the ones in hospitals.

- with Tim Barlass