Fresh fears in Victoria as 400 self-isolate in Shepparton after outbreak went undetected

About 400 people are now self-isolating in the Victorian town of Shepparton as authorities scramble to prevent a major outbreak, amid massive queues outside testing centres.

Victoria recorded six cases on Thursday, fewer than New South Wales, which reported 11 cases, including six local infections. In Queensland, one new case was linked to a return traveller.

In Shepparton, about 180km north-east of Melbourne, local testing sites were overwhelmed after a new outbreak of three cases on Wednesday and queues had already formed before opening hours again on Thursday.

At his daily briefing, the Victorian premier, Daniel Andrews, apologised to Shepparton residents, some of whom had been forced to wait up to six hours for a test.

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He said the government was establishing 11 new facilities in the area and asked for patience.

Andrews also confirmed dozens of residents were now self-isolating as a result of the outbreak, which is believed to have started a fortnight ago and might have spread undetected until this week.

“I would again just make it clear that we have got about 400 people in the Shepparton community that are either cases, contacts or their contacts, so those are three separate groups of people who are all linked through potential chains of transmission,” Andrews said.

“They are isolated at home and they are isolated at home because of one person.”

The fresh fears in Shepparton are heightened by the fact that the outbreak was not detected at the time.

The cases have been traced back to an outbreak at a butcher in Chadstone, in metropolitan Melbourne, which was then spread by a truck driver to Kilmore, north of the city. Authorities say the man initially did not inform contact tracers that he had also visited Shepparton.

However, there were no new cases detected in Shepparton over the past 24 hours, and the deputy chief health officer, Allen Cheng, said it was “not inevitable” there would be more infections in the town of 50,000 people.

About 1,900 people were tested in Shepparton on Wednesday, compared to a usual daily output of 60 tests. Andrews expected a further 2,000 would get tested on Thursday.

All of Victoria’s six new cases on Thursday were in metropolitan Melbourne.

In NSW, the health minister, Brad Hazzard, said the state was on “high-alert”, as he revealed its officials were also concerned that some people were not being honest with contact tracers.

“One of the ongoing problems that we’ve had in NSW but also in Victoria is that people are not necessarily telling us the whole truth and nothing but the truth,” he said.

“Public health only has one interest and that is making sure you remain healthy but also the community retains its health.”

Of NSW’s six locally acquired cases, four were linked to a known cluster and two were under investigation. Three of the four known cases were connected to a growing cluster from a Lakemba GP, which now totals 15 infections.

Restrictions in NSW will be eased from Friday, with up to 500 people allowed to attend open-air concerts, provided they are seated and 4 metres apart.

Victoria will also relax some rules on Sunday, although the changes will be less significant than flagged earlier in the month.

The federal treasurer, Josh Frydenberg – the most senior Victorian in the federal government – renewed his call for Andrews to open the state and “give Victorians back their freedom”.

The 14-day daily case average in metropolitan Melbourne stands at 8.9. Although an average of five was required for a wider opening of retail and hospitality venues, Andrews has indicated in recent days the possibility that “10 is the new five”.

The Queensland government, meanwhile, stood firm on its border closures as new cases continued to emerge in NSW.

The deputy premier, Steven Miles, said on Thursday he was concerned that those new infections may derail plans to open the border at the end of the month.

“Their premier indicated they felt they may be on the cusp of another outbreak not unlike the one they saw after the Crossroads Hotel case,” Miles said.

The prime minister, Scott Morrison, who has been touring Queensland during the state election, said the border closures were hurting the state’s economy.

“I’d love to see Kiwi holidaymakers coming to Queensland ... but they won’t be,” he told 4CA radio in Cairns.

Queensland recorded one new case in the past 24 hours, a return traveller.

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Borders also continue to dominate the public debate in Western Australia, where the premier, Mark McGowan, defended the state’s hard border amid suggestions it was not based on health advice.

The state’s chief health officer, Andy Robertson, said in advice tabled in parliament that he was open to a travel bubble with jurisdictions that had gone at least 28 days without community transmission.

That would see WA open up to all states except NSW and Victoria.

But as he faced criticism from the Liberal party in parliament, McGowan noted that Robertson had also said the border closures were “appropriate and proportionate” but should be reviewed at the end of the month.

“This government, despite the Liberal party, has kept West Australians safe,” he said.