New Delhi, (PTI) Sharpening his attack against GSTN, the company set up to create IT backbone for GST rollout, BJP MP Subramanian Swamy today said he will write to party president Amit Shah and chief ministers of BJP-ruled states to oppose its structure.

"I am writing to Amit Shahji and all BJP chief ministers that while ratifying the constitutional amendments for GST Bill, they should oppose GSTN," Swamy tweeted.

So far, eight states have ratified the GST Constitutional Amendment Bill. These include 5 BJP-ruled states -- Assam, Chhattisgarh, Jharkhand, Gujarat and Madhya Pradesh.

The Goods and Services Tax Network (GSTN) is the special purpose vehicle that was formed under the previous UPA regime to set up the information technology framework for rolling out the indirect tax regime that will replace a string of local levies.

According to Swamy, the equity structure of GSTN is "anti-national".

The government of India holds 24.5 per cent stake in GSTN while state governments, including NCT of Delhi and Puducherry, and the Empowered Committee of State Finance Ministers, together hold another 24.5 per cent. The balance 51 per cent equity is with non-government financial institutions.

Earlier this month, Swamy had written to Prime Minister Narendra Modi raising strong objection to the majority stake for private entities in GSTN to manage and control accounting and collection of GST.

He had urged the Prime Minister to ensure it is replaced by a government-owned structure.

Referring to ownership details of the GSTN company, he had said central and state governments will jointly have only 49 per cent stake in it and the rest with private entities like HDFC Bank, ICICI Bank and LIC Housing Finance that have foreign shareholding.