Deputy Premier Steven Miles today revealed 20 of the 120 passengers on the first flight out of Sydney after border restrictions were imposed at 1am had to be sent back.

Miles said police were patrolling roads along the border and he again urged any Sydneysiders thinking of escaping the hotspot to stay home.

Concern over the threat posed by the Delta variant even overshadowed today’s confirmation that another three people contracted the Alpha variant in Brisbane after a flight attendant was active with COVID-19.

Unlike those cases, people don’t even have to be a close contact of someone with the Delta variant to be infected, and could be struck down in just seconds.

“You only have to be in the same breathing space as someone with this variant to contract it,” Miles said.

“This outbreak really could test all of our systems, everything we have developed over this pandemic, so it’s incredibly important we get this right.”

Chief Health Officer Jeannette Young warned the situation could “rapidly escalate” and suggested the restrictions on Greater Sydney might not be enough to keep Queenslanders safe.

While there is no evidence the Delta variant has spread beyond Greater Sydney, and sewage testing in other areas of NSW has not raised any alarm, much depends on the willingness of Sydney-siders to abide by the restrictions imposed on them.

Young implored Queenslanders to reconsider travel to anywhere in New South Wales, suggesting they could find themselves alongside Sydneysiders and contract the virus without knowing it.

That might be all it takes to spark an outbreak of the Delta variant in Queensland, and Young sought to ensure everyone heard her warning.

“I’m as concerned as I’ve ever been,” Young told journalists.

Miles urged Queenslanders to consider taking up the bookings cancelled due to the border restrictions. He said 20-25 per cent of bookings on the Gold Coast could be cancelled, the Sunshine Coast would also be infected, and up to 40 per cent of Brisbane hotel rooms will suddenly be available around the State of Origin on Sunday.

But Miles and Young implored people to keep listening to updates, and follow the health advice, over the upcoming school holidays.

The new Alpha variant cases came from the flight attendant’s visit to the Brisbane CBD and a Portuguese centre in Ellen Grove.

Young said she was confident that the threat had been contained, but took the opportunity to remind anyone eligible for a COVID-19 vaccine to get the jab as soon as possible.