AAP spokesperson Deepak Bajpai said separate notices have been issued to Yadav, Bhushan, Anand Kumar and Ajit Jha, detailing out a list of charges against them, backed with "evidence". "They have been asked to respond to it in two days. We have mailed them as well as given a copy by hand," Bajpai said.
The rebel leaders, however, claimed they were yet to receive any notice.
The party had earlier referred their cases to the National Disciplinary Committee, after the leaders organised a 'Swaraj Samvad' programme.
Questioning the move, Yadav said the move was against the principle of natural justice as those who had levelled allegations against them were part of disciplinary committee.
Yadav also claimed that in a telephonic conversation national disciplinary committee chairman Dinesh Waghela had told him that the panel is yet to take up the matter.
His remarks came as AAP leader Ashutosh said that a charge sheet is being readied and notice will soon be served to the rebel leaders.
"I am surprised that a person (Ashutosh) who is not a member of the committee is issuing the statement. On Thursday, I called Dinesh Waghela, who is the chairman of the national disciplinary committee. I made him a formal call and asked him about the status of the inquiry against us. He said he is in Goa and there is still no reference of the committee yet. So till yesterday there was no meeting on this.
"I also conveyed to him that this was against the principle of natural justice as two members of the disciplinary committee had levelled allegations against him and Bhushan," Yadav said.
He was referring to party's national secretary Pankaj Gupta and Delhi unit leader Ashish Khetan.
Yadav said, "If a judge is directly or even indirectly related to a case, then he rescues himself from that particular case. How can a complainant itself be a judge?"
Bhushan, Yadav, Kumar and Jha were dropped from top panels of the party at the National Council meeting last month. On Wednesday, the party's Political Affairs Committee (PAC) referred their case to the national disciplinary committee.