Mr Gilmore said some people find it "comfortable" in opposition, but that doesn't solve the country's problems.
In an interview with the Irish Independent, following a damaging week for Labour, Mr Gilmore said this was not the time for Labour to "flinch" from its role in Government.
"While there are people who, you know, may look for easier political options, now is not the time for this Government or for the Labour Party to flinch from the task," he said.
Taoiseach Enda Kenny has also defended the Tanaiste.
In the wake of the loss of the party's fifth TD since entering coalition, the Tanaiste also had a subtle dig at the Labour dissidents who want the party out of Government.
"There are some who, no doubt, would find it more comfortable being in opposition. But being in opposition does not solve the problem.
"The people of this country, I think they expect the people that they elected to Dail Eireann and the parties they elected to Dail Eireann to work to solve the problems – not to exploit them.
"You can sit in opposition. You can moan and complain. You can exploit the problems that are there or you can take the decision that the Labour Party took, which is that we would enter Government – difficult times – and work to solve the problem."
Mr Gilmore said it wasn't always easy being in Government and the Coalition often involved a "compromise".
He said Labour had a "good working relationship" with Fine Gael and his relationship with Mr Kenny was strong.
"This is a Government that is united in its determination to solve the economic problems and what, I suppose, unites that is the Programme for Government that we agreed," he said.
The Tanaiste also reiterated the Coalition will make a decision next week on what action to take on abortion on foot of the recommendations in an expert group report.
"We will have decided the option this side of Christmas," he said.
Mr Kenny said he was "happy" with Mr Gilmore.
"The Tanaiste Eamon Gilmore, leader of the Labour Party, is absolutely focused with the Fine Gael party in Government, as a national government, to deal with our nation's problems that we received a mandate to sort out in respect of which we have signed up for a Programme for Government," he said.