India's southern state of Kerala has announced a two-day lockdown as federal authorities plan to send experts to fight the spread of infections in the country's leading Covid-19 hotspot, Reuters reports.

Kerala, with an active caseload of around 154,000, accounts for 37.1 per cent of India's total active cases. Its positivity rate, indicating the pace of spread in infections, is now the country's highest.

"Special intensified stringent restrictions are being implemented in the areas where the test positivity rate is high," the state's department of disaster management said in a statement announcing a "complete lockdown" from Sunday.