The Louth TD made the claim to UTV on the campaign trail.
“We want the biggest mandate that we can get,” said Mr Adams.
“Maybe we’ll get it this time, maybe we won’t, that’s within the gift of the electorate.
“The election day is the people’s day.
“One thing is for certain, it isn’t a matter of if Sinn Féin will be in government, it’s a matter of when Sinn Féin will be in government.”
All five main parties have travelled around the country to deliver their manifestos for this year's General Election, during a short campaign lasting only three weeks.
Fine Gael leader and current Taoiseach Enda Kenny said: “I accept that the recovery underway has not been felt by hundreds of thousands of people, but that’s why we have to keep it going now."
Fine Gael’s junior partner in the coalition government, the Labour party, have seen their popularity fall in recent months.
Leader Joan Burton said that she was up to the task of retaining her seat, despite recent speculation that she could lose out.
“That’s my challenge over the next week,” she said.
“To say ‘look, we have the experience now, we’ve got the country out of a very tight fix and a difficult time and now we can actually make it very much better.”
Fianna Fáil leader Michaeál Martin has claimed that his party are ready to recover voters lost in the last election.
“A lot of people are indicating to us, ‘we didn’t vote for you the last time, but we’re going to go back to you and vote for you on this occasion’,” he said.
The polls will open on Friday in the Republic of Ireland.