The opposition party fielded senior leaders Ghulam Nabi Azad, Mallikarjun Kharge and Randeep Surjewala to reiterate its demand for a Joint Parliamentary Committee (JPC) probe.
Addressing the media outside Parliament, the leaders cited objections raised by the Defence and Law ministries and demanded that the prime minister and defence minister disclose full facts before Parliament and a JPC.
"Will the prime minister and defence minister now disclose the full facts to Parliament. Only a JPC can investigate the Rafale scam," Azad told reporters ahead of the government's reply in Parliament.
Accusing the government of running away from a JPC probe, Kharge said only a JPC could bring out the truth after summoning the files related to the deal.
"Modiji is continuing to lie as are his counsels, be it Arun Jaitley, Sushma Swaraj or the defence minister (Nirmala Sitharaman)," Kharge said, declaring that they are behaving like "yes ministers".
The government has strenuously denied the Congress' allegations of corruption in the deal and claimed the contract negotiated by it was cheaper than the UPA deal.
The Congress leaders also issued a statement, alleging "dirty secrets, corruption and malfeasance" are tumbling out of the Rafale files, copies of which are also lying in the bedroom of Goa Chief Minister and former defence minister Manohar Parrikar.
Fresh revelations further "expose the brazen corrupt practices" in the Rafale deal, it said.
"The entire spectrum of deception lies at the doorstep of Prime Minister Narendra Modi, who overruled the objections raised and recorded by raised by the negotiations team' in Rafale deal.
"Shocking and stunning revelations expose a concerted conspiracy to cause loss to public exchequer, besides compromising national security. These were all approved by none less than the PM Modi in the Cabinet Committee on Security (CCS)," the Congress leaders said in the joint statement.
Surjewala said the prime minister should reveal what files are lying in Parrikar's bedroom.
"It is clear that the Rafale deal negotiating team raised several questions on the file but Modiji as head of the CCS threw them in the dustbin and caused a loss to the state exchequer," he told reporters.
Citing objections raised by the negotiating team and recorded in the Rafale files, the Congress leaders alleged that Modi raised the benchmark price of the jet deal. The government also waived the "advance and performance bank guarantee and sovereign guarantee", they said.
According to the objections, Modi paid a higher price for Rafales for India compared to Qatar and Egypt and compromised India's national security and India's interests by ignoring the discount offered by Eurofighter, they said.
"Objections on the file read 'As per the prices reflected in Dassault's financial results, it has sold Rafale at a cheaper rate to Qatar and Egypt as compared to India'.
"With the looming threat of China and Pakistan, does it not compromise India's National Security?
"Why did Prime Minister in CCS increase the original Benchmark Price' from Euro 5.2 Billion (Rs 39,422 Crore) to Euro 8.2 Billion (Rs 62,166 Crore). Who is responsible for this loss of exchequer," the Congress leaders asked in the statement.