NEW DELHI -- India's much-awaited tax reform, the Goods and Services Tax, is moving forward. A decade after it was proposed by the previous government, the replacement of a tangle of state taxes with a single national levy is a pillar of Prime Minister Narendra Modi's economic program as he and his government look to launch the tax in April 2017.

But a leader in Modi's ruling Bharatiya Janata Party, parliamentarian Subramanian Swamy, criticized the GST in a recent exclusive interview with The Nikkei, vowing: "I will go to court and stop it."

Swamy's repeated attacks on Raghuram Rajan, the former governor of India's central bank, were a big factor in Rajan's resignation. Swamy's criticism appears to have the backing of senior members of the BJP and the Hindu nationalist organization that forms the core of its support, the Rashtriya Swayamsevak Sangh.

Q: Do you support implementation of the GST?

A: [The] GST will not come. GST has not passed in parliament. Only constitutional amendments have been passed in parliament [in August], and other necessary bills have not yet passed.

Q: What do you mean?

A: It will not come because of the GSTN, the Goods and Services Tax Network [the special-purpose vehicle created to facilitate tax collection]. Either the government will have to scrap the GSTN, which means whole things will collapse, or I won't let it come. I will go to court and stop it.

The GST means that the government has to keep records of all companies and their transactions, and follow it up to see if they actually sell products or services at the place they are claiming. All this tax data, I think it is 6 million companies, has to be pooled in a computer. So, Mr. Chidambaram [the former finance minister in the previous government] created the company, which is called GSTN, that was given this task. [The problem is] who were the shareholders [of GSTN]. Forty-nine percent [of the stock is held by] the government of India, including state governments, and 51% [is] owned by private banks such as ICICI Bank and HDFC Bank -- private banks. All the tax revenue collected will be put in these banks. And these banks and government will sit together to decide how it will be distributed to various states. Now a large portion of these banks' shares are owned by foreigners. So 51% of GSTN is internally owned by foreigners. That means all the tax data will be available to them -- foreigners.

Q: Should it be regulated by the central government?

A: I don't want the government to regulate. The government has enough other work.

Q: Why doesn't government take over responsibility?

A: Yes, let them take over. I don't mind. Kick out ICICI and kick out HDFC, and then 100% will be held by the government. Then there will be no problem, but it won't happen because they have already sunk. It will be a scandal by the time they [create] a new set-up. State governments will want a share, too. It will be beyond 2019, when the next general election is scheduled.

Q: Do you mean it will take longer if the government takes over all the responsibility for implementing the GST?

A: Yes. We need to put it together with a computer program, which is presently with Infosys. The company appointed the wife of the former minister of state for finance [Jayant Sinha] as a director. That may also be a corruption issue. The government could take this over, too. They could cancel the contract with Infosys, but it will take time. If the government takes responsibility, it can be done through Department of Electronics, but they will need a fresh [mandate], et cetera. [It] will take two years. In two years we will have the next general election. Forget GST.

Q: Are there any other leaders in the BJP speaking against the implementation of the GST?

A: They didn't know. Even the prime minister didn't know until I wrote a letter to inform him, as it was kept a secret.

Q: There were suggestions a few months ago that the RSS recommended you to Modi as an adviser to Ministry of Finance. Is that true?

A: These are not formal [proposals]. Now in the system, such things are not formally done. I am an economist and I have given my opinions frankly to them. Some they like, some they don't like, but they respect my integrity. Their interest with me is more [as a spokesman for] Hindutva -- Hindu nationalism. Ultimately, the prime minister also listens to me.

Q: What do you think of Urjit Patel, the new governor of the Reserve Bank of India, the successor to Raghuram Rajan?

A: He has an economics degree from Yale University unlike Rajan, who has management degree.

Q: But he was a deputy governor of the RBI under Rajan, who kept policy rates high. That was a part of your criticism of Rajan, right?

A: No one is responsible for monetary policy except for the governor. In the Indian bureaucracy, people don't give different opinions to their boss. I don't know what Patel did as a deputy governor. We have to see now what he does. I am sure that he will be more sensible than Rajan.

Q: In the future, if Patel acts the same as Rajan will you criticize him, too?

A: No. I have to see, but I can certainly say he is an economist. I don't think he will make the mistakes of Rajan. Rajan is a typical engineer, like a horse with blinders on. When you see [such] a horse, they can only look ahead.

Interviewed by Nikkei staff writer, Yuji Kuronuma