P Chidambaram had offered to stay with the CBI till Monday. (PTI)

Former Finance Minister P Chidambaram's CBI custody in the INX Media case was extended till Monday by a special court today in a hearing that saw an intervention from the Congress veteran himself.

Mr Chidambaram, 73, has been accused of facilitating a huge infusion of foreign funds into the media company INX Media in 2007, when he was Finance Minister, at the instance of his son Karti Chidambaram, who allegedly received kickbacks for his role. Karti Chidambaram -- also named in the case -- is out on bail. P Chidambaram was arrested amid high drama from his home last week by CBI officials who scaled the walls of his house to get in. Since then, he has been in the agency's custody.

The former union minister had offered to stay with the CBI till Monday in an appeal to the Supreme Court yesterday through his lawyer and party colleague Kapil Sibal.

The CBI said in court today that Mr Chidambaram was being "evasive and non-cooperative" and his custody must be extended so that he can be confronted with documents and the other accused in the case.

Calling its arguments "vague", the judge lashed out at CBI and asked why it had not asked for sufficient custody in the first place and was asking for an extension for the second time.

"Will this probe continue for months?" the judge asked when additional solicitor-general KN Nataraj, representing the CBI, said the agency was "questioning him 8-10 hours a day" and the probe was "continuous".

Mr Chidambaram stood up at the accused box to make his case himself, saying there was "no justification" to extend his custody. He had been questioned by the agency for 55 hours and asked some 400 questions, the former union minister said.

"What happened in Supreme Court was a mutual consideration between my lawyer [Kapil Sibal] and the Solicitor General [Tushar Mehta] as the court posted my plea for Monday. My instruction to my counsel was to oppose the plea if the agency asks for five days of custody," he said.

As the additional solicitor-general objected to Mr Chidambaram making his own arguments, the former minister retorted: "I'm not at your mercy; I'm at the court's mercy here."

With Mr Chidambaram agreeing to remain under CBI custody till Monday instead of being sent to Delhi's Tihar jail under judicial custody, the court extended his custody till that day.