The government will hold one more round of consultations with the industry before the rules are finally notified, officials said.
The commerce ministry was confident of putting the SEZ Act and the rules into implementation from November 1 and the officials had also announced it, but now with one more round of consultation to be held it is likely to get delayed further.
The Centre has approved mega SEZs recently with the likes of Reliance, Wipro, Biocon, Ranbaxy and Hewlett Packard.
The investments in SEZ are pegged at about Rs 10,000 crore and they are expected to generate one lakh jobs in one year.
The government has decided to insist on a minimum area of 25 acre for IT, biotech and gems and jewellery and 1,000 hectare for multi-product SEZs.
Reliances 10,000 hectare mega SEZ at Jamnagar, Anil Ambanis SEZ in UP, Serum Institutes pharma and biotechnology SEZ in Pune, Hewlett Packards SEZ for information technology and Biocons biotechnology SEZ in Bangalore have been cleared so far.
Two free trade warehousing zones have also been given the go-ahead.