Raja's request to Lok Sabha Speaker Meira Kumar comes days after Attorney General G E Vahanvati blamed him for various issues before the JPC.
He has also been blamed for the 2G scam by other witnesses before the special CBI court.
Raja met Kumar at her office yesterday and handed over a letter expressing his willingness to appear as a witness before the committee.
DMK members in JPC T R Baalu and T Siva had been pressing Chairman P C Chacko to call Raja as a witness. They also demanded calling Vahanvati again before the panel after he told JPC earlier this month that the controversial press note regarding 2G licences was changed at the last minute by Raja in 2008 with a different pen.
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Chacko is apparently against calling Raja as a witness.
He has told members that as an accused has legal protection, he cannot make fresh revelations before any committee. Therefore, there was no point in calling Raja.
But Chacko is yet to take a final call on the issue.
"If Raja is to be called, he will be the last witness. If DMK agrees on not calling him, then we have concluded calling witnesses before JPC and we would focus on writing the report," Chacko had recently said.
Parliament sources said the Speaker cannot direct any committee to call a person as a witness. In this case, Kumar can forward Raja's letter to Chacko who is currently in Bangalore.