People queue in cars at a Covid-19 drive-through testing center at Bondi Beach in Sydney on December 20, 2020. Photo: AFP/Steven Saphore

Sydney has seen a two-day dip in coronavirus cases after Australian authorities imposed a snap lockdown and residents flocked to testing centers in record numbers, but officials have cautioned the outbreak is still “evolving.”

A Covid-19 cluster on Sydney’s northern beaches has grown to 90 cases since emerging last week, sending the area’s picturesque seaside suburbs into a lockdown.

Despite record testing, eight new coronavirus cases were confirmed Tuesday after 15 cases the previous day – raising hopes that the city’s five million residents may yet be able to celebrate Christmas with family and friends.

Long queues have snaked outside testing sites across Sydney, with more than 83,000 people tested on Monday and Tuesday in New South Wales, a state of 7.5 million people that includes the sprawling harbourside city.

State Premier Gladys Berejiklian praised the “outstanding” public response, but said the virus threatened to continue spreading because those infected visited gyms, pubs and restaurants across Sydney.

“What remains our concern is that even though the case numbers are relatively low compared to what we’ve experienced in previous days, the number of venues that are impacted grows,” she said.

Berejiklian said the two-day dip in case numbers appeared to show health strategies were paying off, but cautioned that the situation was still “evolving” and case numbers could “creep back up.”

An intense contact tracing effort is underway, with chief health officer Kerry Chant saying “many thousands” of people have been ordered to isolate at home for 14 days.

Authorities have promised to review restrictions, including caps on home visitor numbers, on Wednesday, the day before Christmas Eve.

Australia has largely been successful in containing the virus by quickly shutting its borders at the beginning of the pandemic. Only returning citizens, New Zealanders and people with special exemptions can enter.

However, the virus has leaked out of hotel quarantine – where international travelers must spend 14 days before entering the community – on several occasions, including most recently in Sydney.

The city has been virtually sealed off from the rest of the country in efforts to keep other regions virus-free heading into the holidays.

Australia has now recorded about 28,200 Covid-19 cases and 908 deaths in a population of 25 million.