His remarks came after the CBI, which is investigating the Saradha chit fund scam, has summoned him for questioning in connection with the financial transactions of 'Jago Bangla', the TMC mouthpiece newspaper.
O'Brien is the publisher of the party's official newspaper.
In a statement, the TMC MP said, "Earlier, when Parliament was in session I was served a notice. I immediately wrote to the CBI stating that since Parliament was in session I would appear on a date after the session has concluded."
Brien said, however, a day before he was supposed to meet the CBI, "they called and informed me that I am not required to meet them".
"I also sent them a letter reconfirming the same," he said.
According to the CBI sources, the agency is investigating the links of arrested Bengali film producer Shrikant Mohta with the promoters of Rose Valley.
The agency suspects that Mohta had allegedly cut a deal of several crores with the promoters of Rose Valley and a portion of that was diverted to the bank accounts of 'Jago Bangla'.
O'Brien said since February, he has not received any intimation from the CBI.
"Now, during this Parliament session, I was served a notice asking me to appear before them on August 1. I have sent them a letter stating that I would meet them after this session is over on August 7," Brien said.
"Let me also add that I will not be intimidated. In February, I had agreed to appear before the CBI after the session was over, but the CBI chose not to meet me. This time too I am ready to meet them," he said.
The CBI may also question the TMC leader regarding the sale of several paintings of party chief Mamata Banerjee which were purchased by owners of several ponzi scam companies allegedly at a huge price, the officials said.
Earlier in the day, O'Brien took to Twitter and said that he and senior party leader Subrata Bakshi, the publisher and editor respectively of "Jago Bangla", had been summoned by the agency a month ago regarding some clarifications.
He said he was served a CBI notice at 2 p.m. on Friday, at almost the same time when his party brought up the motion to oppose the amendments to the RTI Act in the Rajya Sabha.
"Jago Bangla is Trinamool's official newspaper. Publisher: Derek O'Brien. Editor Subrata Bakshi was summoned by CBI a month ago to seek clarifications. Now, publisher served a notice at 2 p.m. July 25. Trinamool Motion in RS (Rajya Sabha) to oppose amendments to RTI Act started at 2 p.m., July 25," he tweeted on Thursday.
The CBI, which is probing the multi-crore chit fund case under the direction of the Supreme Court had also summoned Bengali artist Subhaprasanna and businessman Sibaji Panja earlier this month.
( With inputs from IANS )