Volcker, who had set conditions for his taking charge of the ailing firm, said, "At this point, those conditions have not been met, but we can always look for miracles," the Post quoted Volcker as saying in a statement Monday.
The Post also reported that Andersen has hired a turnaround firm, which has led to speculation that a bankruptcy filing may be imminent.
A bankruptcy filing, however, wouldn't shield the firm from criminal litigation, bankruptcy experts told the Post.
The Wall Street Journal reported Monday that the former Federal Reserve chairman was on the verge of quitting the rescue effort.
"It's a question of whether you have a useful role to play," Volcker told the Journal.
"It comes to the point where, if conditions aren't met, you don't have a useful role to play," Volcker said. "That's a conclusion, not a resignation."
Volcker's preconditions to taking charge of Andersen were a settlement with federal prosecutors on a charge of criminal obstruction; and resolution of civil litigation connected to the accounting firm's audits of Enron Corp.
An Andersen spokesman, Dan Hill, told the Post that Alvarez & Marsal, a New York firm, "is working with Andersen to reform and restructure under the guiding principles of Volcker."
Alvarez & Marsal was hired in late March, and Bryan P. Marsal is serving as Andersen's "chief restructuring manager," Hill told the Post. Marsal's office declined to comment, referring inquiries to Andersen, the Post said.
Andersen is run by a five-member administrative board headed by Andersen's U.S. managing partner, Larry Gorrell, according to the Journal.