The CBI on thursday rejected the plea seeking monitoring of 2G probe by  committee of experts saying that it is  independent in its work and that  "it has done fairly credible job".

"Until this hearing, your lordship on each occasion and on looking into the status reports did not find anything wrong in our investigation," senior advocate KK Venugopal, appearing for CBI, told a bench of Justice GS Singhvi and Justice AK Ganguly.

He said a very high-profile case is under investigation and investigating officers are working day and night and a large number of persons from different spheres are assisting the probe.

The CBI said no other organisation in the country has investigated the economic offence of such a high magnitude with such a speed.

"You are driving the agency to speed up the investigation and the results are coming. CBI is very independent in its work. We have not accepted the report of a ministry. We have not accepted the report of TRAI on zero loss. CBI is independent from the control of the government.

"The facts that a minister from coalition partner and the MP from the coalition partner and daughter of the then chief minister of Tamil Nadu has been arrested show the independent character of CBI requiring the probe not to be monitored by any other," Venugopal said opposing the plea for appointing two or more persons of eminence to monitor the probe.

"What is the situation for appointment of two persons for day-to-day functioning of CBI? Would it not, in the end, result in slowing the speed of the investigation carried out so far because they would have to report to you (court) to show progress of the probe?" he said while asking the bench to reject any plea for creating a body like Special Investigation Team (SIT).

"There is no ground to show the investigation so far was not done in a good manner," he added.

The NGO, Centre for Public Interest Litigation (CPIL), has alleged the CBI investigation in 2G spectrum scam was "less than honest" as it was not probing many high-profile persons including Home Minister P Chidambaram.

In order to assist the court, it is imperative and essential to entrust the matter to at least two persons of eminence for monitoring the probe," advocate Prashant Bhushan, appearing for the NGO, had submitted.