New Delhi, Nov 8 : The Union Finance Ministry on Tuesday said the move to withdraw Rs 500, Rs 1,000 currency notes is the biggest "surgical strike" by the government to curtail black money in the economy.

"This is the biggest and the boldest step by the government for containing black money. It is like a surgical strike on black money," tweeted Revenue Secretary Hasmukh Adhia.

Prime Minister Narendra Modi, in a sudden address to the nation on Tuesday, announced that Rs 500 and Rs 1,000 denomination notes are being withdrawn from midnight and will now become "mere paper".

Modi said this was being done to tackle the menace of black money in the country, which has sapped the economy.

The Prime Minister said that the Rs 500 and Rs 1,000 denomination notes can be deposited in banks and post offices, and also exchanged across the bank counter by showing government-issued ID proof.

The decisions come after a cabinet meeting.