The CPI-M on Friday "strongly denounced" Defence Minister Manohar Parrikar's statement that India should revise its "no first use" nuclear weapon policy.
"This has serious implications both for India's security concerns and for India's standing in international relations," the Communist Party of India-Marxist said.
"This statement represents a complete reversal of the long standing position of India as a country that champions a nuclear weapon free world and consistently stood by its commitment for peaceful use of nuclear energy.
"The statement clearly indicates that this government is negating India's established stand on use of nuclear weapons in war.
"It jeopardises India's security concerns by undermining the declared good neighbourly relations approach," the CPI-M said in a statement.
"Further, it undermines India's efforts for membership of international bodies like the UN Security Council and the Nuclear Suppliers Group.
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"The Defence Minister's contention that these are his personal opinions is completely untenable," the CPI-M said.
"As a member of the cabinet collective in a parliamentary democratic system, under oath to the Indian Constitution, such opinions that are contrary to India's long established policy direction is a reflection of the complete lack of 'governance' of this government.
"If the Defence Minister wishes to air his personal opinions, then he may do so after resigning from the Cabinet," it said.
The CPI-M urged Prime Minister Narendra Modi, now visiting Japan, to clarify the government's commitment to India's long standing stand of universal nuclear disarmament and the non-use of nuclear weapons in war.