Australian officials have warned Sydney residents to brace for a surge in Covid-19 cases as the country's largest city logs record infections for the second straight day despite a weeks-long lockdown to stamp out an outbreak of Delta variant, reports Reuters.

"Just based on the trend in the last few days and where things are going, I am expecting higher case numbers in the next few days and I just want everyone to be prepared for that," New South Wales Premier Gladys Berejiklian told reporters in Sydney, the state capital.

Sydney has reported a record 279 locally acquired cases of Covid-19 over the past 24 hours, up from the previous high of 259 the day before. New South Wales has reported a record 291 cases, up from 262, with one new death, raising the state total to 22 in the latest outbreak, all in Sydney.