Earlier, the government had said it was looking at divestment in Indian Oil Corporation, Steel Authority of India Ltd and ONGC in the first quarter of 2011.
The follow-on public offer was originally scheduled to open on March 15, but has now been rescheduled.
The public offer in which government plans to sell 5 per cent (427.77 million shares) was scheduled to open on July 5 and close on July 8.
ONGC will file the red herring prospectus for the FPO by February 25, by which time it hopes to have five more independent directors on the company's board to meet the Securities and Exchange Board of India's listing requirement.
The government plans to sell 5 per cent of its stake in Oil and Natural Gas Corporation through the further or follow-on public offering which at current prices can fetch up to Rs 13,500 crore (Rs 135 billion).
The government by mid-January will appoint merchant bankers for the mega Rs 13,500 crore (Rs 135 billion) public offering of Oil and Natural Gas Corp (ONGC), which is targeted to hit the market in March.