The Bharatiya Janata Party (BJP) and the Trinamool Congress termed Gandhi's remarks as "damage control".
A BJP MP said Prime Minister Manmohan Singh should resign if he had any dignity left. Communist Party of India-Marxist (CPI-M) said it was for the Congress to speak on the ordinance confusion.
BJP leader Arun Jaitley said Gandhi's remarks that the ordinance was "nonsense" were "grandstanding" and aimed at "damage control".
"This is a highly belated realisation of what constitutes nonsense. If heads don't roll, then this is only a grandstanding intended to show to the country that the government can make mistakes, only the first family of the Congress doesn't make mistakes," Jaitley told a news channel.
Making a dramatic appearance at the Press Club of India Friday during a party press meet, Gandhi said the government was "wrong" in preparing an ordinance that seeks to save convicted lawmakers from disqualification and that, in his opinion, "it is completely nonsense and should be torn up and thrown away".
Jaitley said the United Progressive Alliance government had twice approved the decision to save convicted lawmakers from immediate disqualification - once as a bill and later as an ordinance. The bill has been referred to the parliamentary standing committee.
"On both occasions, the Congress party has supported it. It is not that today the Congress was unaware of this," he said.
"The whole country is waiting to see if the prime minister has any self-respect left ... Whether he accepts the decision of his cabinet being called nonsense," Jaitley said. The prime minister is in the US to attend the United Nations general assembly meeting.
The ordinance, approved by the union cabinet Tuesday, reverses the Supreme Court judgment mandating the immediate disqualification of lawmakers convicted for a criminal offence punishable with a jail term of more than two years.
BJP president Rajnath Singh attacked Gandhi over his remarks.
"I would like to ask Rahul Gandhi for his comments about the UPA (United Progressive Alliance) government. If the ordinance is nonsense, then what is his comments about the government," Rajnath Singh told reporters in Chennai.
BJP MP Varun Gandhi tweeted the prime minister should resign if he has any dignity left.
"If the prime minister has even a shred of dignity left, he should resign immediately upon his return to the country," he said.
Trinamool Congress MP Derek O'Brien said the Congress was attempting damage control.
"While PM is in Washington DC, the Congress party too are in DC: Damage Control," he said.
CPI-M MP Nilotpal Basu said Gandhi's remarks reflect utter confusion in the ruling dispensation.
"It is for them (the Congress) to comment. This (Rahul Gandhi's) statement betrays complete confusion on what is going on," Basu told IANS.
Social activist Kiran Bedi tweeted: "Its embarrassing to see the considered bright/brilliant passionately defend decisions of their party until a Yuvraj comes and overturns them," he said.
--IANS (Posted on 27-09-2013)