Addressing concerns expressed by some half-a-dozen Opposition ruled states, Home Minister P Chidambaram on Tuesday said the National Investigating Agency Act may be revisited.

"We will revisit the NIA Act, if needed," he told media persons at the end of a day-long conference of chief ministers on internal security.

Participating in the meeting, chief ministers of NDA-ruled states that the new National Investigation Agency would 'disturb' the federal set up of the country and resented that states were not consulted before the new anti-terror laws were framed.

Admitting that nearly half-a-dozen states expressed some 'reservations' over the NIA, Chidambaram said he would write to all chief ministers detailing the contents of the NIA and tell them to write back to him if they require clarifications.

"My letter will clarify all their (Chief Ministers') doubts," he said.