The commercial operation of the first of the 2x1000 MW reactors of the Indo-Russian project was expected by May, the Nuclear Power Corporation of India Limited (NPCIL) has said.
The second unit was also likely to be delayed with the expected commissioning pushed to December, it said.
Minister of State in the PMO V Narayanasamy had informed Lok Sabha earlier this month that the first unit was expected to be commissioned by April and second by October.
The project, hit by protests by locals over safety concerns, has missed several targets for commissioning since December last year.
The Atomic Energy Regulatory Board (AERB) had given clearance for the second heat up and full system tests of the unit-1 on January 24.