NEW DELHI: Prime Minister Narendra Modi on Tuesday strongly defended his government's decision to ban high value currency notes, saying it was the right step taken at the right time to rid the Indian economy of tax evasion and black money.

Modi, speaking in the Lok Sabha in reply to motion of thanks to the President's address, mocked at the opposition protests against the November 8, 2016, decision of spiking Rs 500 and Rs 1,000 notes that led to a huge currency crunch in the country.

He likened the decision with surgery conducted on the human body.

"When can you have an operation? When the body is healthy. For demonetisation, good economy was needed and this was a proper time. Our economy was doing well and our (demonetisation) decision was taken at the right time," Modi said.

"The move was calculative. The decision was taken after Diwali when trade (across the country) was high," he said, adding the move was like the Swachh Bharat mission to clean the economy of ill-gotten wealth accumulated by evading tax.

"Like Swachh Bharat, the decision on demonetisation is a movement to clean India (of corruption and black money)," Modi said.

He said he was aware of political risks but "I am not concerned about the elections".

"I am concerned about my country," he said, urging the opposition "to join the mainstream and contribute in the development of the country."

Modi took a dig at Congress Vice President Rahul Gandhi for his tom-tommed "earthquake" exposure on the Prime Minister's alleged involvement in corruption.

"We were ready for discussion, but instead of discussion the opposition was more concerned about giving TV bytes," he said, referring to the Winter Session that was completely washed out in opposition protests against demonetisation.

Hailing his decision of forming a Special Investigation Team (SIT) to bring back black money stashed in foreign banks, Modi said: "The Supreme Court quoted on March 26, 2014 that since 1947 nobody thought of bringing back black money from foreign countries."