Former Taoiseach Mr Albert Reynolds has denied he is exploiting the fallout from the Flood tribunal report to gain revenge against Mr Ahern.
Mr Reynolds deepened the Taoiseach's political woes when he revealed he told him of his suspicions that Mr Burke was corrupt when Mr Ahern succeeded him as Fianna Fáil leader in 1994.
He dismissed suggestions he went public to embarrass Mr Ahern, who is widely believed to have played a pivotal role in Mr Reynolds's failure to secure the party nomination for the 1997 Presidential election.
Speaking on Radio 1's Today with Pat Kenny, Mr Reynolds said Mr Ahern was entitled to set aside his "unproven" suspicions of Mr Burke. Mr Ahern subsequently appointed Mr Burke as Minister for Foreign Affairs.
Mr Reynolds said: "Every Taoiseach is entitled to make their own choice. He carried out his own investigation, and came to a different conclusion. He is entitled to do that."
However, Mr Reynolds made it clear he held Mr Ahern responsible for his "humiliating" failure to win the Presidential nomination. He said the Taoiseach had convinced him to run for the Presidency. He had only reluctantly agreed, and would have retired gracefully had he known there was a groundswell of support within Fianna Fáil for Mrs Mary McAleese. He felt Mr Ahern let him down at the critical moment. "Bertie made the difference between winning and losing."