India's government has asked the country's states to keep a sharp lookout for any new variants of the coronavirus, citing an increase in Covid-19 cases in China and other parts of the globe.

Health Minister Mansukh Mandaviya met senior government officials on Wednesday to discuss the matter, with all those present wearing masks - a practice that has not been mandatory in most parts of the country for several months.

China has seen a surge in infections after ending strict Covid restrictions, while data from the World Health Organisation shows infections have risen in countries like Japan, South Korea and the United States in recent days.

"In view of the sudden spurt of cases being witnessed in Japan, the United States of America, the Republic of Korea, Brazil and China, it is essential to gear up the whole genome sequencing of positive case samples," Health Secretary Rajesh Bhushan wrote in a letter to the states on Tuesday.

"Such an exercise will enable timely detection of newer variants, if any."

The government has asked all states to ensure that samples of positive cases are sent to the country's 54 designated genome sequencing laboratories.

Some opposition leaders and Twitter users in India have called for a suspension of flights to and from China. A government source, who was not authorised to speak to the media and declined to be identified, said there was no such plan.

Mandaviya also asked participants in a cross-country march organised by the opposition Congress party to ensure they are vaccinated and follow safety measures like wearing masks.

With more than 44 million Covid cases to date, India has reported the most in the world after the United States. Its number of confirmed infections has, however, fallen sharply in the past few months, with about 1,200 cases being reported every week at present.

- Reuters