Charlie Flanagan has questioned whether the Green Party will be "on the back of that bike" in another coalition government going forward.
The former Justice Minister was speaking after he announced he is to retire at the next general election.
Boundary changes mean his Laois/Offaly constituency will be broken up into two new three seaters and the TD informed Fine Gael he intends to stand in neither of them.
Deputy Flanagan told The Pat Kenny Show he would not be supporting a Sinn Féin coalition going forward.
"I certainly wouldn't be voting or supporting a Sinn Féin/Fine Gael government," he said.
"I watch the opinion polls like all politicians do, and we mightn't readily admit that we watch them closely.
"The opinion polls over the last two years, steadily and consistently show, that the leaders in the polls are Fianna Fáil and Fine Gael.
"I have no doubt that if Leo Varadkar and Micheál Martin continue to work assiduously, and prioritise the needs of the people of Ireland that must be prioritised, I think there's every chance that a Fianna Fáil/Fine Gael government can be returned the next time.
"Whether the Greens are on the back of that bike, I don't know."
'We can be proud'
Deputy Flanagan said he believes Ireland is not celebrated enough.
"We've had 100 years of independence, Ireland is a respected country all over the world," he said.
"Our political system is almost free of corruption compared to most countries in the world.
"Ireland is still a reasonably safe country, so after 100 years we can be proud of how far our country has come.
"I don't hear that; I don't hear it in the media, I don't hear it in the streets.
"I do believe you'd hear it in the offices, or you'd hear it on the part of the people who pay their bills, who work.
"I'm not saying of course that things are without flaws - we have really serious issues in terms of housing, in terms of health, in terms of cost of living."
'Government needs to do more'
Deputy Flanagan said he doesn't believe the Government has failed people 'who get up early in the morning'.
"I don't believe it has failed them, but I do believe it has to continue working for and on their behalf," he said.
"I think it needs to do more for them, and I think the budget next month will show that in terms of rewarding enterprise, rewarding effort, rewarding those people who keep the wheels of our country moving.
"Often times they get forgotten about in terms of media hype and media alarm, and the business of media and newspapers," he added.