India's defence ministry said Tuesday a controversial report about the country's defeat by China in a brief, bloody 1962 border war would remain classified due to its "sensitive" nature.

The comments came after excerpts from the Henderson Brooks Report analysing the causes of India's defeat were reportedly uploaded on the Internet by veteran Australian journalist Neville Maxwell.

The report could not be accessed from India, and there was no immediate explanation for why the website was blocked.

But India's NDTV television network website cited passages from the document it said were posted by Maxwell, who reported extensively on the war.

India in the war "acted on a militarily unsound basis of not relying on our own strength but rather on believed lack of reaction from the Chinese", NDTV quoted the report as saying.

Maxwell said on his website he always had access to the report but had been waiting for it to be declassified, the Press Trust of India national news agency said.

Maxwell, now nearly 90, decided to put out a large part of it in the public domain because of India's unwillingness to release it, according to the news agency.

"As I see it now, I have no option but rather than leave the dilemma to my heirs, to put the report on the Internet myself," Maxwell was quoted on his website as saying by news magazine India Today.

In 1962, a Chinese offensive overwhelmed India's unprepared defence forces, media reports at the time said, with the magazine Time describing the Chinese offensive as a "human-sea assault".

The month-long war ended with China calling a unilateral ceasefire and withdrawing from India's northeast while retaining Aksai Chin, a strategic corridor linking Tibet to western China.

India's defence ministry declined to comment on the reported contents of the report.

"Given the extremely sensitive nature of the report, which is of current operational value, it is reiterated the government has classified it as a top secret document," the defence ministry said, according to the Press Trust of India.

"As such, it would not be appropriate to comment on the contents uploaded by Neville Maxwell on the web," the ministry said.

Ahead of general elections due to kick off next month in India, the alleged Chinese war revelations have given the opposition a chance to fire more salvos at the governing Congress party which is struggling in opinion polls.

Many historians blame Congress Prime Minister Jawaharlal Nehru for misreading the border situation and allowing the 1962 defeat to occur.

BJP spokesman Ravi Shankar Prasad was quoted by local media as asking, "What is the government trying to hide by making the Indo-China war report classified?"

While there is heavy trade between India and China, relations are still dogged by mutual suspicion -- a legacy of the border war in which India got a bloody nose.

The countries have held a series of talks to resolve their border dispute but the frontier still bristles with tensions.