Twenty-two Covid-19 patients at a hospital in India were killed on Wednesday when the oxygen supply to their ventilators was disrupted by a leak.

The tragedy comes as India battles severe shortages of medical supplies during a fierce second wave of coronavirus infections.

The 30-minute leak from an oxygen tanker stationed outside Dr Zakir Hussain Hospital in Nashik, about 200 kilometres north of Mumbai, cut off supply to the ventilators of more than 60 critically ill patients.

"The oxygen supply was restored within half an hour and oxygen is being supplied through the same tanker now," local official Suraj Mandhare told reporters after the leak.

Weeping relatives gathered at the hospital, which was treating 170 Covid-19 patients in total, many of whom were moved to other facilities after the incident occurred.

Indian Prime Minister Narendra Modi said the leak, which took place in Maharashtra state -- the epicentre of the country's Covid outbreak -- was "heart-wrenching".

"Anguished by the loss of lives due to it," he tweeted.

The state's chief minister Uddhav Thackeray ordered an inquiry. 

The deaths come a week after Thackeray asked Indian pilots to airlift oxygen supplies to the region to alleviate severe shortages as Covid-19 infection numbers climb.

Hospitals in India's capital New Delhi have come perilously close to seeing their oxygen supplies run out as infections continue to spike in the country of 1.3 billion.