Australia's most populous state, New South Wales (NSW), has reported a double-digit rise in new locally acquired cases of Covid-19 for the third straight day as officials fight to contain an outbreak of the highly contagious Delta variant.

"Since the pandemic has started, this is perhaps the scariest period that New South Wales is going through," state Premier Gladys Berejiklian told reporters in Sydney.

NSW has imposed tough restrictions in Sydney, Australia's largest city and home to a fifth of the country's 25 million population, with health officials saying transmission could be happening even through minimal contact with infected persons.

Read the full Reuters story here.