Sinn Féin says the second referendum on the Lisbon Treaty in October will see the electorate presented with the very same document it rejected last year.
The party has launched its campaign for a 'no' vote in the referendum today.
It is accusing the Government of wasting an opportunity to renegotiate a better deal on the treaty.
Sinn Féin says the treaty was drafted by right-wing politicians who caused the current recession and claims a 'yes' vote would be bad for the Irish economy.
It says the guarantees secured by the Government are a smokescreen that actually amount to nothing.
“The Lisbon Treaty was a bad deal for Ireland when it was presented to the people last year and it remains the very same bad deal," Sinn Féin deputy leader Mary Lou McDonald said.
"Sinn Féin will continue to fight for a better deal for Ireland and for Europe. In order to get a better deal we must reject this treaty once again," she added.
"I am calling on the voters to do just that.”