"Turning opposition untouchable not good for Anna's democratic movement," BJP spokesman Tarun Vijay said in a twitter posting.
Earlier, however, Vijay had termed government conceding to Hazare's demands as a victory nation's collective conscience.
"A victory for nation's collective conscience. Just the beginning," said Vijay in a previous tweet.
Noted lawyer Shanti Bhushan and his son Prashant Bhusan were included in the Lokpal Bill drafting committee which has a total of 10 members including five from the government.
Baba Ramdev, who had joined the agitation, had also objected to the inclusion of the Bhushans in the committee, alleging it showed nepotism.
Hazare had brushed aside the criticism on inclusion of father-son duo and virtually ruled out any change in the nominees, saying the focus is on having an effective anti-graft measure.
The Government on Friday had agreed to constitute a 10-member Joint Committee, including civil society members to draft a stronger Lokpal Bill.
The veteran activist broke his 98-hour-long fast on Saturday morning after the government issued a notification announcing setting up of the committee to draft an effective Lokpal Bill.
The committee 10-member committee does not have any representative from the opposition parties.