"We would have known the extent of infections, how much is the spread, about two weeks back. The delay is about two weeks," Dr Manoj Murhekar, a task force member and director of the National Institute of Epidemiology, told Reuters on Thursday.
A survey of 24,000 people was now underway with indigenously developed test kits and data would be available by the end of May, he said.
Two members of a research group advising the government said the delay caused by the inconsistent Chinese kits was longer than two weeks.
Two other members of the group said another factor that has hindered the collection of the data is that health authorities have been more focused on testing high-risk groups and containment, and slow in efforts to mount systematic surveillance.