Green Party leader Trevor Sargent has described Fianna Fáil and the Progressive Democrats as "a disgrace" to the men and women of 1916 and the principles they fought for.
Speaking at the launch of his party's annual conference in Kilkenny yesterday evening, Mr Sargent said the Government's current policies had created a very unequal and divided society in Ireland.
"Maybe Frank Dunlop, the former Fianna Fáil government press secretary, understands what makes this Government tick more than most," he said.
"He told the Mahon tribunal . . . that when a crooked Fianna Fáil politician was bought, he stayed bought."
He said: "When you see who dines in the Fianna Fáil tent at the Galway Races, it is clear that this Government is well bought by those who benefit most from Irish society being more divided and vulnerable than ever."
Speaking in advance of the planned official celebrations next month to mark the Rising's 90th anniversary, Mr Sargent said the two Government parties were "a disgrace to the men and women of 1916 and the principles of sovereignty and equality for which they died".
In his opening speech of the conference, which is themed around the issue of energy, Mr Sargent also criticised the Government for creating the "most car-dependent country in the world" and for having "frightened off" large wind energy companies from establishing operations in the State.
Mr Sargent also reiterated the position of the Green Party, agreed last year, that it would not make a pre-election pact with any party.
He said the key policies for the party in any future negotiations on joining in government were transport, housing, childcare and energy.
The guest speaker, general secretary of the Irish Congress of Trade Unions (Ictu) David Begg, told the conference that during the current partnership talks the trade unions were looking for "a radically different model" than previous agreements, which focused on economic growth through modest wage increases and tax cuts.
He said any new agreement had to recognise that offsetting wage claims with tax cuts was counter-productive and that maximising economic growth for its own sake no longer had a social dividend.
He also said the recognition that sustainable development was in keeping with the common good had to be recognised in social partnership, while economic growth needed complementary social development.
Priorities for Ictu during partnership talks were labour market reform, healthcare reform, improved childcare infrastructure and services, and access to education and training for workers.
The Irish Times Environment Editor, Frank McDonald, also a guest speaker at the conference, criticised the Government's approach to the environment, claiming the country "is now being wrecked by half-baked policies that fail and are known to fail".