Chennai, Nov 12 (IANS) Tamil Nadu Chief Minister M. Karunanidhi Friday put up a staunch defence of his tainted DMK colleague and central minister A. Raja and said there was no need for him to quit or for the party to speak to the Congress on the subject.

The issue found echo in the Tamil Nadu assembly as well, with the ruling DMK hitting out at the AIADMK over J. Jayalalithaa's unconditional offer of support to the Manmohan Singh government.

"What wrong has he done? He only went by the rules," Karunanidhi told reporters here amid growing clamour from the opposition in New Delhi and Chennai for the communications and IT minister's sacking from the cabinet on account of the 2G spectrum scam.

"He is not guilty. No auction (of spectrum) was made during the tenure of Pramod Mahajan and Arun Shourie. They followed the first come first serve policy. The same method was adopted in the allotment of 2G spectrum," he said.

On the Comptroller and Auditor General (CAG) report, Karunanidhi said he could offer comments only after the report is released.

The CAG Wednesday submitted to the government its report on the controversial 2G spectrum allotment that is understood to have caused a loss of over Rs.170,000 crore to the national exchequer.

Referring to Jayalalithaa's offer of support to the central government if the DMK backs out, Karunanidhi said they had knocked at the door but it was closed.

Asked whether he would speak to Congress on the issue, the chief minister replied: "There is no need to speak to the Congress on the spectrum issue."

The issue came up in the assembly too.

"You knocked the doors at Delhi and it has not opened," Finance Minister K. Anbazhagan told AIADMK's O. Pannerselvam in an oblique reference to Jayalalithaa's offer to the Congress Thursday.

Pannerselvam retorted that the doors would open soon.

At which, Karunanidhi added: "We will know whether the doors will open or not."