Queensland's health minister has defended a decision to rapidly close the state's border to Adelaide indefinitely amid a coronavirus outbreak in the city.
Chief Health Officer Jeannette Young ordered all travellers arriving in Queensland from the South Australian capital into mandatory hotel quarantine from 11.59pm on Monday night.
The COVID-19 outbreak in Adelaide ballooned to 18 people, but only one new case was discovered there over the last 24 hours.
Health Minister Yvette D'Ath says they didn't pull the trigger too early on travel restrictions with those infected with the virus in Adelaide visiting a large number of venues and being out in the community.
"We have had thousands of people arrive in Queensland from Adelaide in the last seven days, thousands of people coming from Adelaide in the last seven days," she told reporters on Tuesday.
"We can't take any chances. We need to make sure that we are acting quickly and putting in place reasonable measures to keep the people of Queensland safe, and that's what we're doing."
About 7000 people who arrived in the state from the City of Churches in the past seven days have been told to go into self-isolation for seven days.
Far less people are currently in self-isolation in the SA capital, but Ms D'Ath says being cautious has allowed the Sunshine State to go 64 days without a case of community transmission.
Perhaps unsurprisingly, the health minister said just five people from AFL-mad Adelaide who were already in Queensland would be barred from attending Wednesday night's rugby league State of Origin decider.
Ms D'Ath said the border would remain closed until Adelaide goes for 28 days without a new unlinked case of virus spread.
She pointed out that Queensland travel restrictions did not apply to all South Australians, only to Adelaide residents.
"Unlike Tasmania, unlike the Northern Territory, unlike Western Australia we have not taken the step of saying that all of South Australia are now having to go into quarantine if they travel, it is only from those local government authorities in the greater Adelaide area," she said.
"We believe that's a measured response and that is the advice that the chief health officer is giving me is that today."
Ms D'Ath also announced a further relaxation of COVID-19 rules in Queensland from 4pm on Tuesday.
She said poeple would only have to keep two metres from other people in venues like pubs and restaurants.
Ticketed events in venues like stadiums and cinemas will also be able to fill 100 per cent of seats.
"We can only do this because of the great work that Queenslanders have done in making sure that they're complying with the restrictions," Ms D'Ath said.