The office of India's National Security Advisor, M.K. Narayanan, and other government offices in India were targeted by hackers believed to be from China, according to a report.
"This was not the first instance of an attempt to hack into our computers," Narayanan reportedly told The Times.
He said the attacks on Indian government offices were on 15 December, the same day some US companies also reported that their systems were hacked.
Narayanan was on Saturday appointed as governor of the Indian state of West Bengal. He has yet to assume the new post.
Google said last week that it had been hit by hacker attacks in mid-December. It said it detected a sophisticated and targeted attack on its corporate infrastructure originating from China, that resulted in the theft of intellectual property from the company.
The attack on India came through an email with a PDF attachment containing a Trojan virus, which allows a hacker to access a computer remotely and download or delete files, Narayanan said.
Narayanan and other officials were not immediately available for comment.
"People seem to be fairly sure it was the Chinese. It is difficult to find the exact source but this is the main suspicion. It seems well founded," Narayanan said in the interview with The Times.
India and China fought a war in 1962, and a border feud has worsened over the last one year.
India has placed curbs on the Indian operations of Chinese technology companies like Huawei Technologies. The Indian government recently indicated it has security concerns about the use of telecom equipment from Chinese vendors, particularly in border areas.