Canberra, Dec 24 : Following the discovery of a fast-growing Covid-19 cluster in Sydney, Australians have been forced to celebrate Christmas within locked state borders due to the imposition of stricter curbs to stem the virus spread. Traditionally Christmas in Australia is spent with family and friends, and many people take the opportunity to travel elsewhere in the country to reconnect with distant relatives, reports Xinhua news agency. However, as the Sydney cluster threatened to spread, recently reopened interstate borders were slammed shut again, barring residents from Australia's largest city from entering. By Christmas Eve on Thursday, the Sydney cluster had grown to over 100 cases, less than was feared but enough to warrant harsh restrictions on those within the outbreak area. State authorities split Sydney's Northern Beaches into two sections, imposing a strict lockdown on the region where the cluster originated. So far the State of New South Wales (NSW), of which Sydney is the capital, has named over 100 venues as being visited by a known case. Anyone who also attended during the same period is considered a close contact and required to self-isolate for 14 days whether they return a negative reading or not. On Thursday, NSW recorded nine new cases overnight, with seven linked to the cluster. Two cases are still under investigation. There were 60,000 people who came forward to be tested over the past 24 hours. The cluster has now increased to over 100 cases. The state of NSW currently accounts for 4,823 coronavirus cases and 53 deaths. Australia has so far reported a total 28,238 cases and 908 fatalities. /IANS