Micheal Martin has said that proposals to radically change the way Fianna Fáil works are under consideration with the guiding principal of empowering members.
A series of rule changes would be put before the Ard Fheis arising from the consultation process.
He was speaking at the opening of a special parliamentary party meeting ahead of the new Dáil term.
Mr Martin said the current Government had launched almost no new major policies and had displayed a thin skin when criticised.
"Fianna Fáil had a clear and distinct role to play in opposition."
Sinn Féin and the Technical group might have signalled that they intended to take the route of total opposition, he said, but "Fianna Fáil would be true to its promise to be constructive."
Mr Martin said the crisis in the Euro had exposed what he said were the enormous failings of the ECB.
"Fianna Fáil will continue to push for a more open debate about the future development of the European Union, particularly its economic management."
Turning to the Mahon report, which is expected to criticise former Taoiseach Bertie Ahern, Mr Martin pledged to respond quickly and comprehensively to all matters, no matter how difficult they were.
He contrasted this stance with that of Fine Gael and Labour, who he accused of trying to run away from the findings of the Moriarty report.
Members of Fianna Fáil gathered in Dublin for the latest in the series of parliamentary party meetings ahead of the return of the Dáil on Wednesday.
The economy and the social impact of the recession were top of the agenda, against the backdrop of the huge problems facing the party itself.
A year ago, when Fianna Fáil last met ahead of the Dáil term, then Taoiseach Brian Cowen gave an interview to RTÉ’s Morning Ireland, which attracted controversy.
This interview was seen as starting the slide in the party’s fortunes - a decline that led to an election in which the party lost 58 seats.
Yesterday, the Fianna Fáil party Whip said TDs and Senators would not be allowed to individually back candidates seeking nominations to run in the presidential election.
Speaking on RTÉ's The Week in Politics, Seán Ó Fearghaíl was responding to speculation that Senator David Norris may be considering re-entering the race for the presidency and could obtain support from some Fianna Fáil Oireachtas members.
Fianna Fáil is to table legislation to set up a statutory body to deal with the problem of households overwhelmed by debt.
Outlining the plan, Finance Spokesman Michael McGrath said Fianna Fáil was proposing an Independent Debt Settlement Office which would deal with all household liabilities and not just mortgage arrears.
The process would operate using personal insolvency trustees who would negotiate with financial institutions on behalf of households and individual.
He said it was important that all the banks dealt in a uniform way with those in trouble and he was not convinced that was happening at the moment.
