A constitutional amendment is necessary to advance Lok Sabha polls, Chief Election Commissioner James Michael Lyngdoh said in Hyderabad on Saturday.

Union Law Minister Arun Jaitely had sounded out one of the election commissioners, T S Krishnamurthy, about the idea, he said. "Krishnamurthy told him that 'it cannot happen just like that'."

Lyngdoh, who is on a visit to Andhra Pradesh to review the progress of work for the issue of electoral photo-identity cards, reiterated his opposition to the idea of holding simultaneous polls to the Lok Sabha and state assemblies.

"Lok Sabha elections are not a problems, but the simultaneity of state assemblies' elections is a problem," he observed.

He said elections in states such as Bihar, Uttar Pradesh and Andhra Pradesh were held at different points of time, 'but tomorrow if everybody is doing it at the same time, there the bad states will do whatever they want'.

But 'if the central government goes ahead and gets the Constitution amended, then the Election Commission will have to abide by it', he admitted.

"If they make constitutional changes necessary for bringing together the two elections, then naturally we all have to live with that."

He pinpointed several practical problems for holding simultaneous polls. Deployment of forces was one of the biggest hindrances.

"The (Union) home ministry is able to provide not more than 400 companies of central paramilitary forces while each one of the problem states needs that much force. If you fill up one state with 400 companies, then the other states will do whatever they want. So you will have bad elections, plenty of cheating. If you want to accept these results as they are, then it is fine.

"The Election commission has a mandate to conduct free and fair elections and it has to make sure that it happens," he said.