Describing it as an "unprecedented" moment in the country's history, he said the creation of the one-nation, one-market and one-tax system would greatly benefit the common man.
He took stock of various elements involved in the roll-out and directed the officials that maximum attention be paid to cyber-security in IT systems linked to the GST, the Prime Minister's Office (PMO) said in a statement.
The GST, for whose roll-out a law was enacted last year, will overhaul the indirect tax regime in the country.
The meeting, which lasted for over two-and-a-half hours, was attended by Finance Minister Arun Jaitley, and top-most officials from the Ministry of Finance, the PMO and the Cabinet Secretary.
The prime minister said the implementation of GST from July 1 is the culmination of the concerted efforts of all stakeholders, including political parties, trade and industry bodies, the statement said.
He described the GST as a "turning point for the economy, unprecedented in history", the PMO said.
During the course of the meeting, the prime minister specifically reviewed aspects of implementation such as IT readiness, HR readiness, training and sensitisation of officers, query handling mechanism, and monitoring, the statement said.
He was informed that GST systems such as IT infrastructure, training of officials, integration with banks, and enrolment of existing taxpayers will be in readiness well in time for the July 1 implementation date, it added.
Information security systems were discussed in detail. A Twitter handle - @askGst_GOI has been started for real-time answering of queries.
An All India toll-free phone 1800-1200-232 has also been activated for this purpose.