While no new cases of COVID-19 were reported overnight in Queensland, the number of tests done in a 24-hour period doubled, to 8,265, as people responded to concerns over an outbreak in Sydney.

That is the most tests since Queensland had clusters in Logan and Ipswich three months ago. In the previous week, Queensland tested a greater proportion of the population than any other state, including NSW – and with better outcomes.

There are still 10 active cases in Queensland, all of those in hospital. However, more than 3,000 people are subject to self-quarantine notices, requiring them to isolate at home, and hundreds more are currently in police-controlled hotel quarantine. Authorities are determined to keep the defences strong.

Recent overseas arrivals, and anyone visiting from greater Sydney, will be in hotel quarantine or self-isolation over the festive period. Quarantine workers are also being tested more regularly out of concern the infection might escape.

NSW Premier Gladys Berejiklian today confirmed seven new cases linked to the northern beaches cluster, as well as an infection in a healthcare worker who transported patients from the airport to quarantine. That worker has also seemingly infected a colleague. It comes after a bus driver who transported flight crews was infected.

Another 10 cases were reported in overseas arrivals already in hotel quarantine. Berejiklian called on other states to “step up” and take in more travellers, reminding premiers that Sydney’s role as a gateway city put the state at greater risk.

“We don’t stand here and tell you how many were Queenslanders or Victorians,” Berjiklian said, referring to the 10 cases in quarantine.

Berejiklian urged anyone who had travelled from the northern beaches to self-isolate in line with health advice. However, Berejiklian referred only to those visiting regional NSW, not those crossing the border. Queensland officials are concerned there are visitors who have not taken adequate precautions.

Police erected barricades on roads into Queensland overnight after random intercepts revealed an alarming number of motorists arriving from NSW with the wrong permit, or no permit at all. All vehicles are now being stopped.

Queensland Police chief superintendent Mark Wheeler said 57 vehicles containing 115 people were denied entry to the state overnight.

Wheeler sent a message to anyone trying to “game the system,” believing they could avoid a fine, that police would be waiting “with an unwanted Christmas gift of $4,000 that you won’t be able to return.”

Police are also greeting all flights, although airlines have cancelled services after a weekend surge.

Berjiklian said the situation in greater Sydney was still “volatile” and even though the number of new cases was down on yesterday, the number of venues subject to a public health alert was up again. One case from the northern beaches cluster was detected in Victoria, similar to the situation with a woman who travelled into south-east Queensland without realising she had been infected.

Berejiklian praised contact tracing efforts, and said “I challenge any other state to have this much information publicly available at that short amount of time.”