Speaking on RTÉ Radio, Mr Ahern said it was critical that the DUP and Ian Paisley provide clarity about their willingness to share power with Sinn Féin so that the Sinn Féin Ard Fheis on policing could proceed.
He said it would be inexcusable, inexplicable and a huge tragedy if the currrent process failed.
Also speaking on RTÉ Radio, Sinn Féin's chief negotiator Martin McGuinness said the DUP leadership need to come up to the mark and state whether they agree to power sharing.
He said all sides need to be involved and there was another difficulty in that Ian Paisley and Gerry Adams do not talk.
He also said one of the biggest disadvantages is that Bertie Ahern had only spoken to Mr Adams once since Christmas on the back of criticism that he made to a member of the Taoiseach's department.
Ahern intends May or June Election
Mr Ahern also said it was still his intention to hold the General Election in either May or June.
He said if Fianna Fáil were returned to power, it would not be reasonable for his party to object to support from Sinn Féin in the next Dáil.
But he said Fianna Fáil would not enter coalition discussions or a pact with Sinn Féin, or create a Government with them on the basis of Sinn Féin's policies.
