India's official death toll from Covid-19 crossed 500,000 on Friday, even as many experts flag underreporting of cases across the country. 

The daily update from the country's federal health ministry showed the number of fatalities reaching 500,055, up 1,072 in the previous 24 hours.

Total infections stood at 41.9 million, according to the statistics, second only to the United States. 

Case numbers have jumped in recent weeks due to the highly infectious Omicron strain but rates have slowed in recent days and the health ministry last week said there were indications of a plateau in virus cases in several parts of the country.

Experts said the Omicron wave would not cause many deaths or hospitalisations, but several states imposed restrictions on movement and have only now started easing them.

Many analysts believe India actually reached the 500,000-death mark last year when it was hit by a devastating spike in cases due to the Delta variant that brought its health care system close to collapse. 

The wave saw at least 200,000 deaths as hospitals ran out of oxygen and patients scrambled desperately to source medicines. 

A study by a US research group last year suggested that anywhere between 3.4 million and 4.7 million people had died.

For months now, several states have been reconciling their death toll and adding "backlog" deaths as India's Supreme Court ordered state authorities to provide compensation to families.

Kerala, Bihar and Prime Minister Narendra Modi's home state of Gujarat are among those to have added thousands of old deaths to their existing tolls.

Last month, the Modi government asked states to stop mandatory testing of contacts of those who test positive, unless they had underlying health conditions.

But soon after the order the government told states to ramp up testing as numbers dropped.   

Booming sales of home coronavirus self-test kits have also fuelled fears of underreporting of cases across the country.