Modi is due to address the nation in a radio broadcast on Sunday, when he is expected to lay down fresh guidelines after 65 days of lockdown.
In an open letter marking one year into his second term, Modi on Saturday urged people to follow lockdown rules to stop the spread of the pandemic as there was a "long battle" ahead.
"Our country (is) besieged with problems amidst a vast population and limited resources," Modi said, adding that laborers and migrant workers had "undergone tremendous suffering" due to restrictions.
India has recorded 173,763 COVID-19 cases and 4,971 deaths, making it the ninth most-affected country globally, Reuters data showed.
While fatality rates in India have been comparatively low, experts warned that the pandemic's peak has not been reached as new infections are increasing.
Earlier on Saturday, state carrier Air India said it had to recall a plane heading to Moscow to bring home stranded citizens after a crew member tested positive for COVID-19.
Officials are nervous about the pandemic spreading through villages as millions of jobless migrant workers return home from cities.
Rights activists and the opposition have criticized Modi's handling of the pandemic, accusing him of announcing an abrupt lockdown that left the poor in the lurch and forced thousands to walk or jostle for space on buses and special trains to reach home while fearing infection.
More than 100 migrant workers have died either in accidents or due to starvation as they tried to return to their villages, the home ministry official said.