Victoria will press ahead with easing virus restrictions on Sunday, despite a worrying spike in infections that has added 69 COVID-19 cases in just five days.

The state reported 18 new coronavirus cases on Thursday, as its numbers leapt again.

This week’s surge – which has brought Victoria to 81 active cases of the deadly virus – has closed schools and businesses and sent a nursing home into lockdown.

“Clearly, we do have community transmission in Victoria and I want to reiterate the message to Victorians to take this issue seriously,” Health Minister Jenny Mikakos said.

“Many of these cases are people with very, very mild symptoms, but they’ve done the right thing and gone and been tested and that is how we will manage the spread of the virus.”

Among Thursday’s confirmed cases is a third person who attended the Black Lives Matter rally in the Melbourne CBD on June 6.

The man, who is in his 20s, was one of two cases of community transmission reported on Thursday. Deputy chief health officer Annaliese van Diemen said he was not infectious at the June 6 protest, and possibly acquired the virus there.

• Virus ‘eradicated’, Northern Territory to open borders

Tweet from @NSWHealth

Dr van Diemen said more cases from the BLM marches appeared unlikely.

“We would hope most people would have been discovered. Given the time frame since the protest – it’s now been almost two weeks, so we’re getting to the end of the incubation period,” she said.

The BLM protester works at H&M at Melbourne’s Northland Shopping Centre. The shop was closed for cleaning on Thursday.

There were also six new cases in returned overseas travellers, while the remaining infections are in contacts of other patients or are still being investigated.

Another new case is a household contact of someone linked to the Croydon Family Practice outbreak. That cluster now has five confirmed infections.

There are also cases in a worker from Learning Centre Pakenham, in Melbourne’s outer south-east, and a one-year-old child at Guardian Childcare and Education in Prahran, in the inner city.

Victoria is now clearly the outlier among Australian states. Only NSW also had new infections on Thursday – three in returned travellers from a record 17,400 tests conducted on Wednesday.

Victoria’s spike also comes ahead of a planned easing of virus restrictions on Sunday (June 21).

• See Victoria’s current and planned virus measures here

Tweet from @VicGovDHHS

“We have erred on the side of being very careful in terms of how we manage this issue. We are reviewing the numbers and how we’re trending on a day-by-day basis,” Ms Mikakos said.

“At this point in time, in terms of the changes that we have already announced for Monday, they will be proceeding.”

Later Premier Daniel Andrews also said the easing of restrictions was likely to go ahead.

“I don’t believe that it will be the case that we need to change those settings,” he said.

“But they are reviewed each and every day, and that’s why people adhering to the social distancing, people continuing to take this seriously, is very, very important.

“Today’s numbers and yesterday numbers are a timely reminder, if anyone needed that, that this is far from over.”

Old protocols cleared Ruby Princess

Assessment protocols that allowed the COVID-carrying Ruby Princess cruise ship to enter Sydney should have been scrapped and re-written, a senior NSW Health official says.

A draft document for cruise ship health procedures dated February 19 should have been updated from March 10, nine days before the vessel docked, NSW Health executive director Dr Jeremy McAnulty told an inquiry on Thursday.

The change would have been in accordance with updated information regarding suspected COVID-19 cases from the Communicable Diseases Network of Australia.

It would have included testing of all passengers who had been to any country within 14 days, as well as acute respiratory illnesses with or without fever.

Dr McAnulty said the risk assessment process used by the heath assessment panel to deem the ship low risk before arrival was “no longer relevant” when the ship was granted access to berth in Circular Quay on March 19.

“Have you just told me in effect that should all have been scrapped and rewritten?” Commissioner Bret Walker SC, overseeing the inquiry, asked.

“That’s correct, once the CDNA guidelines changed to all countries,” Dr McAnulty replied.

Dr McAnulty told the inquiry the update meant the ship should never have been labelled low risk and said the NSW Health draft document was not updated to reflect changes due to the “enormous busyness” the department faced at the time.

More than 20 coronavirus deaths in Australia have been linked to the 2700 passengers who disembarked the Ruby Princess when it arrived in Sydney on March 19.

The inquiry continues.

-with agencies