India's capital New Delhi will lock down over the weekend as authorities grapple with a fresh surge in coronavirus cases, partly fuelled by the fast-spreading Omicron variant.

The country was battered by a devastating Covid outbreak last year that overwhelmed hospitals and crematoriums, but daily case numbers had since then stayed reasonably low until last week.

Delhi's new restrictions came the same day the sprawling megacity's chief minister, Arvind Kejriwal, announced he had been infected and was suffering "mild symptoms".

Kejriwal said he was isolating at home and urged those in contact with him in the past few days to get tested.

The capital last week closed gyms and cinemas, as well as imposing an overnight curfew in an effort to stem the spread.

All residents besides essential workers will now be asked to stay home from Friday night to Monday morning.

"The government is fully prepared to fight any Covid situation," the city's deputy chief minister Manish Sisodia said in a Tuesday address.

More than 200,000 people died across India last spring after a wave of Delta variant infections that brought the healthcare system to its knees.

India's 481,000 known Covid deaths is the world's third-highest toll, behind the United States and Brazil.

But under-reporting is widespread and some studies have estimated its actual toll could be up to 10 times higher.

India began rolling out vaccinations for teenagers on Monday and will offer booster doses for people over 60 from next week.