Union Minister M Venkaiah Naidu today urged Leader of Opposition in Rajya Sabha Ghulam Nabi Azad to back the crucial GST bill in the Monsoon session of Parliament starting July 18. Sources said, in a telephonic conversation with Azad, the Information and Broadcasting Minister, who earlier held the charge of Parliamentary Affairs, sought Congress' support for the passage of the GST bill. The government has also proposed holding talks with opposition Congress to iron out differences on the issue. A meeting of top Congress leaders like Azad and Anand Sharma with Finance Minister Arun Jaitley on the issue is likely to be held in a day or two. The Constitution amendment bill for roll-out of GST is pending in Rajya Sabha for a long time and the government is keen to see its passage. The Goods and Services Tax seeks to bring a uniform tax structure subsuming a number of imposts and the government claims that it will help add 1 to 2 per cent to the country's GDP. Top Congress leaders had yesterday deliberted on the strategy for the session with party president Sonia Gandhi at her residence where GST was also discussed. Congress has been pressing for a GST cap of 18 per cent as part of the Constitutional Amendment bill with which the government is not in agreement. Insiders say the demand has become a sticking point, but Congress may relent and agree to a cap in the statute and not as part of the Constitution bill.