Mayaram said the concerns over the pace of implementing economic reforms were "overstated".
Keeping that much money out of the banking system has created a liquidity deficit that has forced banks to borrow as much as RS 1.6 trillion from the central bank to meet daily funding needs.
His officials are working on a series of steps to attract at least $20 billion in new investment to fund the deficit without depleting India's $300 billion in forex reserves.
The wholesale price index, the main inflation indicator, rose an annual 6.84 per cent in February, higher than the 6.54 per cent rise estimated by analysts.
The FinMin has built up a cash surplus of about Rs 80,000 crore.