India's novel coronavirus cases surpass half a million - ministry

India reported over 17,000 new coronavirus cases over the last 24 hours, pushing the country's total above 500,000, federal health ministry data showed on Saturday, with infections surging in major cities including the capital New Delhi.

India has the world's fourth-biggest outbreak of the virus that causes COVID-19, below only the United States, Brazil and Russia in confirmed infections, according to a Reuters tally.

Infections are expected to continue rising steadily in India. Experts advising the federal government say the authorities should now prioritise reducing mortality over containing the spread of the virus.

"Our focus should be on preventing deaths and not really getting bogged down because of the numbers. Numbers are going to increase," said Dr Manoj Murhekar, a member of India's main coronavirus task force and director of the National Institute of Epidemiology.

The COV-IND-19 study group, led by Bhramar Mukherjee, a biostatistics professor from the University of Michigan, forecasts that India could see between 770,000 and 925,000 cases by July 15.

As infections mount swiftly and hospitals become stretched, some cities like New Delhi are scrambling to build temporary facilities with thousands of beds to quarantine and treat COVID-19 patients.

The city of around 20 million people only has around 13,200 beds for COVID-19 patients and will add at least 20,000 in coming weeks, with some facilities manned by army and paramilitary doctors.

Staff shortages are likely to be a concern as hospitals are swamped and more temporary facilities open, experts warn, although health authorities in some Indian cities are pushing for improved risk-based categorisation of patients.

"We have to ensure those who really require treatment aren't denied services," said Dr Giridhar R. Babu, an epidemiologist at the Public Health Foundation of India who is advising the southern state of Karnataka.