Addressing his second press conference of the day, Mishra also claimed that a "few AAP members" have told him that Mr Kejriwal has made up his mind to "sack (Health Minister) Satyendar Jain" by coming Wednesday.
In his earlier press conference, Mr Mishra alleged he was an "eyewitness" to Mr Jain handing over Rs 2 crore to Mr Kejriwal.
Mr Mishra said he would be at the ACB office at 11 AM tomorrow.
He questioned the "inaction" over a report submitted by him to Mr Kejriwal in August 2015 on the alleged Rs 400-crore water tanker scam during the tenure of the Sheila Dikshit government.
However, the Karawal Nagar MLA did not elaborate whether he would share details on his sensational claim that he saw "Kejriwal taking Rs 2 crore cash from Jain" with the ACB.
"Secondly, several party members have told me that Kejriwal has made up his mind to sack Jain in the next two-three days and preparations are on to get his resignation by Wednesday," he told reporters.
Through his tenure as a minister, Mr Mishra has repeatedly flogged the scam, relating to alleged irregularities in hiring of private tankers to supply water, which he claimed involves Ms Dikshit and even a "few people in the AAP government".
Mr Kejriwal had constituted a fact-finding committee to probe the allegations in June 2015. The report was submitted in August 2015, recommending an FIR against Ms Dikshit.
The then Lt Governor Najeeb Jung had forwarded it to the Anti-Corruption Branch, which in turn had registered FIRs against both Ms Dikshit and Mr Mishra.