NEW DELHI (AFP) - India will allow more domestic flights and interstate train services to operate but keep schools shut as the nation of 1.3 billion further eases its lockdown despite growing concern about rising coronavirus cases.

The South Asian nation recorded almost 550,000 virus infections on Monday (June 29), including 16,475 deaths, making it the fourth worst-hit in terms of case numbers after the US, Brazil and Russia.

But with the economy struggling during the shutdown, the authorities have sought to restart activities while maintaining "containment zones" to try and limit the virus spread.

"Domestic flights and passenger trains have already been allowed in a limited manner. Their operations will be further expanded in a calibrated manner," the Home Affairs Ministry said late on Monday in its "Unlock 2" guidelines.

Prime Minister Narendra Modi is to address the nation in a speech on Tuesday.

The new measures - which also include a shorter night curfew - will come into force on Wednesday and remain in place until the end of July.

The night curfew would be further relaxed to permit the movement of people and goods for work or when they take public transport, the ministry said.

Schools, metro trains in cities, cinemas, gyms and swimming pools would remain closed, while activities in "containment zones" would still be severely restricted, it added.

Under a major easing of the lockdown in early June, places of religious worship, hotels, restaurants and shopping malls were allowed to reopen.

The virus has particularly hit India's densely populated cities and there are now major concerns for New Delhi which has overtaken Mumbai with more than 85,000 cases.

The government has been criticised over a lack of testing that experts say has hidden the true number of cases in India.