India reported a smaller rise in daily coronavirus infections for a third straight day yesterday, as the government said it was working to boost vaccine supplies to avert deaths beyond the pandemic toll of more than 270,000.

The number of deaths in the past 24 hours rose over 4,000 for the fourth time in a week, with yesterday's 311,170 new infections representing the lowest single-day rise in more than three weeks.

Federal health officials warned against interpreting a "plateauing" in the rise as a sign for complacency, however, and urged states to add intensive care units and strengthen their medical workforce.

The warning comes after the World Health Organization issued a grim warning that the second year of Covid-19 was set to be "far more deadly".

Even though India is the world's largest vaccine-producing nation, it has fully vaccinated only 2.9% of its population of 1.35 billion, or just over 40.4 million people, health ministry data shows.

Vaccines were resulting in milder infections and preventing loss of life, worst affected states told Health Minister Harsh Vardhan yesterday, according to the statement.

India could protect itself from future waves of the pandemic by vaccinating 510 million people, or more than 40% of its population, over the next few months, surgeon Devi Shetty told news channel India Today in an interview.

"There is no other solution and that is the cheapest solution," he added. "It is the best solution if we have to save millions of lives."

India's massive second wave of infections began in February, putting hospitals and medical workers under unprecedented pressure.

But cases have fallen steadily in states hit by an initial surge of infections, such as Maharashtra and the northern state of Delhi, after they imposed stringent lockdowns.

The capital, Delhi, extended its lockdown by a week to next Monday to build on recent gains, Reuters partner ANI reported.

Total infections have risen by more than 2 million this week and deaths by nearly 28,000. Deaths rose by 4,077 on Sunday.

On Saturday, federal health officials said the proportion of positive tests had dipped to 19.8% this week from 21.9% last week, sparking hopes that daily infections had begun to stabilise.

But surges have been seen in states such as Tamil Nadu in the south and rural areas. The government issued new guidelines yesterday to curb the spread of the virus in India's vast countryside, urging more surveillance of flu-like symptoms.

On Friday, The WHO, besides warning of a higher death toll on the pandemic's second year, urged wealthy countries to stop vaccinating children and instead donate doses to poorer nations.

"We're on track for the second year of this pandemic to be far more deadly than the first," said WHO director-general Tedros Adhanom Ghebreyesus.

"I understand why some countries want to vaccinate their children and adolescents, but right now I urge them to reconsider and to instead donate vaccines to Covax," said Tedros, referring to the global vaccine-sharing scheme.