India is considering plans to seal off coronavirus hotspots in Delhi, Mumbai and parts of the south while easing curbs elsewhere as a way out of a three-week lockdown that has caused deep economic distress, officials said on Wednesday.

The sweeping lockdown of India's 1.3 billion people to prevent an epidemic of COVID-19, the respiratory disease caused by the virus, ends on Apr 14 and Prime Minister Narendra Modi is due to take a decision this week on whether to extend it.

Scenes of poor migrant workers and their families walking long distances on empty highways to their homes in the countryside have increased the pressure on Modi to re-open parts of Asia's third largest economy.

More than 80 per cent of the positive cases of the coronavirus have been traced to 62 districts - less than 10 per cent of India's landmass - according to government data.

These are concentrated in Maharashtra, home to financial capital Mumbai, Delhi and Tamil Nadu, Telangana and Kerala.

Many parts of the country have not reported a single case.

Such a skewed geographical spread strengthens the case for a more targeted approach under which the affected area and its neighbouring district will be cordoned off, health officials said.

"To manage coronavirus, we are working on a cluster containment strategy," said Health Ministry joint secretary Lav Agarwal, leading the effort to tackle the outbreak.