Both the New York Times and CIA-backed threat intelligence firm Recorded Future had hinted that the October 2020 outage was caused by malware infiltrated by Chinese-linked attackers.
Indian federal power minister R.K. Singh told the news agency ANI: "We don't have evidence to say that the cyber attacks were carried out by China or Pakistan.
"Some people say that the group behind the attacks in Chinese, but we don't have evidence. China will definitely deny it."
The Times of India which carried the report, said suspicion of China being behind the outage had started after Recorded Future's document was put online.
Singh confirmed that some attacks had taken place on the country's northern and southern region load dispatch centres, but claimed the malware could not reach the operating system.
Two teams which investigated the outage had submitted reports, he said.
"The outage was caused by human error and not due to the cyber attack. One of the teams submitted that a cyber attack did happen but it was not linked to the Mumbai grid failure."
The claims about Chinese involvement were partially supported by the government of Maharashtra, the state of which Mumbai is the capital.
The claims made by Recorded Future were backed by Robert Lee, head of the security firm Dragos, which specialises in security for industrial control systems.
iTWire has contacted the NYT, Recorded Future and Dragos for comment.
