New Zealand has extended a strict lockdown in its largest city, requiring 1.7 million people living in Auckland to remain indoors for at least another week to snuff out small outbreaks of the highly infectious Delta variant of coronavirus, reports Reuters.

Health authorities have recorded 33 new cases of the Delta variant of Covid-19, all in Auckland, which was higher than 23 and 20 cases reported over the last two days.

"It's clear there is no widespread transmission of the virus in Auckland, but so long as we have new cases emerging, there are risks," Prime Minister Jacinda Ardern told a news conference, announcing the decision to prolong the city's lockdown until September 21.

After that, Auckland will move from level 4 to level 3, which means curbs will be eased slightly but offices, schools and public venues would still stay shut.