Richard Boyd Barrett has appealed to parties that take a left-wing stance to put up a "united front".
The Solidarity-People Before Profit TD wants parties such as Sinn Féin, The Social Democrats and The Greens to join forces.
His comments come with nine days remaining in the general election campaign.
Deputy Boyd Barrett told Newstalk radio's Pat Kenny Show that he wanted a "grand coalition" of the left to ensure Fine Gael or Fianna Fáil are not returned to power:
He said: "I think we have a historic opportunity to move beyond them for the first time in Irish political history. I think that's an exciting prospect.
"They have had their 100 years running the State... in recent years they've left us with a mess in the most basic things: housing, health, the cost of living, the climate and many other things.
"The polls are showing - and I think the trend is showing - that more than 50% of people are looking for something different.
Appealing for unity on the left, he added: "When we do come together - as we have done on a number of campaigns... we have been very, very effective.
"I would appeal to all of the left - including some of the radical left - to build a united front that offers people a genuine alternative to Fianna Fáil and Fine Gael, who I think most people can't tell the difference between the two of them."
He also argued that third-level education is being "chronically underfunded" here.
The People Before Profit politician suggested: "Do people know that the amount of State support for horses is bigger than for students?
"That's why our universities are now stumbling down the international league tables."
He also criticised the Labour party's past record, claiming the party's history is a "test case of the disastrous consequences of repeatedly propping up Fianna Fáil and Fine Gael".
Mr Boyd Barrett was also asked whether he believes a left-wing government could deliver on the policy pledges that have been made by the different parties.
On the subject of housing, he responded: "During the boom period we were building 90,000 houses a year. Can we ramp up construction to a very high level? Clearly, we've shown a capacity to do that.
"The problem at the moment is that a lot of people left the construction industry because they saw the boom-slump cycle.
"We need, in our view, a State construction and local authority-led approach to these things - where construction workers know they will have some overtime income and employment security."