The head of India's opposition Bharatiya Janata Party (BJP), tipped to win ongoing national elections, has ruled out any change in the country's "no-first-use" nuclear weapons policy.

The BJP sparked speculation about an end to the doctrine last week when its manifesto said that the party would "revise and update" India's policy.

"The no-first-use policy for nuclear weapons was a well thought out stand... We don't intend to reverse it," BJP President Rajnath Singh told the Hindustan Times newspaper in an interview published Monday.

The policy was adopted after a series of nuclear tests in 1998 during the last BJP-led coalition government which led to international condemnation and an embargo being placed on the country by Western powers.

The policy was intended to gain India greater acceptability as a nuclear power, despite it not being a signatory of the 1970 UN Nuclear Nonproliferation Treaty which aims to prevent the spread of nuclear weapons.

The BJP is predicted to clinch power under elections which began on April 7 and end with results on May 16.

Any BJP government under hardline prime ministerial candidate Narendra Modi, a proud nationalist promising strong leadership, is expected to have a more muscular foreign policy.

Any change in nuclear policy would be of most significance to India's rivals Pakistan and China.

Neither reacted to news of the possible review and analysts have pointed out that the "no-first-use" policy is a mere promise that could be ignored by New Delhi in a conflict situation.

China was the first country to adopt the "no-first-use" nuclear policy in 1964, but nuclear-rival Pakistan, with whom India has fought three wars, does not have a similar position.