Congress media in-charge Randeep Surjewala said Modi was made aware of this entire fraud by a whistleblower, Hari Prasad, by way of a written complaint filed July 26, 2016 and acknowledged by the PMO.
Surjewala said whistleblower Hari Prasad had written to the Prime Minister's Office as early as July 2016, alerting the government about the "biggest bank loot scam in 70 years" in independent India.
"What does the Prime Minister do? Nothing. What does the Finance Ministry do? Nothing. What does the Corporate Affairs Ministry do? Nothing. What does the Financial Intelligence Unit of the Finance Ministry do? Nothing," Surjewala told reporters.
"You are in power, a fraud is happening under your nose. What were you doing and how did they let the accused escape? Face the truth and answer questions."
He also asked Prime Minister Modi what the fugitive billionaire was doing with him at the World Economic Forum in Davos in January.
He said the "chhota Modi" was part of a delegation travelling with Prime Minister Modi despite "the complaint against him".
Issuing a clarification, the government said Nirav Modi was not part of the delegation which accompanied PM Narendra Modi in Davos.
"There was no meeting which took place between Neerav Modi and PM. He was a part of a Group photograph. The photograph was shot after he got out of a bilateral meeting on the sidelines of WEF," government sources said.
They said the Invest India, an agency dedicated to investment promotion and facilitation, had arranged this photo Op at the WEF Davos and Nirav Modi attended the EEF Davos meeting on his own as many businessmen do.
Nirav Modi case: How PNB was defrauded of Rs 11,400 crore
Punjab National Bank had rocked the financial world on Wednesday with the revelation that it had detected "fraudulent and unauthorised transactions" worth 11,500 crore at one of its branches in Mumbai.
The fraudulent transactions are reportedly linked to billionaire diamond merchant Nirav Modi, against whom the bank had filed a complaint with the CBI last month.
Nirav Modi was initially charged last month with causing a wrongful loss of Rs 280.70 crore to PNB in 2017 after hatching a conspiracy with two bank officials to defraud the bank.
The other partners who were allegedly involved in fraudulent transactions were Nirav's wife Ami, brother Neeshal and maternal uncle Mehul Choksi, who owns Gitanjali Gems.
On Wednesday, PNB filed two more complaints against Modi after it realised that the fraud could involve at least Rs 11,500 crore of its money.
The estimated scale of the fraud of Rs 11,500 crore is more than eight times PNB's net profit of Rs 1,325 crore in the financial year ended March 2017. The crisis could impact the bank's profitability this year.
Nirav had left India on January 1, and is believed to be in Switzerland. Nirav's wife Ami, a US citizen, and business partner Mehul Choksi departed on January 6.