Tripura health minister Badal Choudhury said deaths so far in the northeast state were unusually high, with doctors ordered to contain the mosquito-borne disease before it "gets out of hand".
"So far we have received reports of 20 deaths and more than 400 people afflicted with the disease in the past one week," Choudhury told AFP by telephone.
"The exact death toll could be higher as we are still getting reports of malaria deaths from interior areas," he said.
"We are taking it very seriously as we do not get reports of so many deaths in the initial stages of the monsoon.
"So we need to be prepared to fight the disease soon before it gets out of hand."
Hundreds, and perhaps thousands, of people die every year from malaria in India particularly during the monsoon season when the mosquitos carrying the parasite breed.
India's remote northeast region, which is forested and cut by rivers, suffers heavily from the disease whose symptoms include fever, vomiting, diarrhoea and jaundice.
Parts of northern Tripura bordering Bangladesh are the worst hit so far this year, and teams of doctors have been sent to the area and fumigation services stepped up.
"We have put on alert medical teams across the state to ensure the disease doesn't spread to newer areas," the minister said.
"Most of the casualties were in tribal dominated areas of Gandachera and the Longtharai Valley in the northern district of Dhalai."
According to the World Health Organisation, hundreds of people died from malaria in 2012 in India out of 627,000 deaths globally.
But a study published in The Lancet in 2010 concluded that the number of deaths in the world's second most populous country was more than 200,000 each year.
The study said the WHO's reporting methods were flawed as it depended on patients who have been diagnosed by a doctor. Many deaths in India occur at home, rather than in a hospital or a clinic, the study said.