Harris had until the end of the coalition's five-year term in March to go to the polls but has been paving the way for an earlier election, announcing 10.5 billion euros ($A17.1 billion) in tax cuts and spending increases in last month's budget.
The package takes advantage of Europe's healthiest public finances just as US president-elect Donald Trump's plans to slash US corporate taxes and impose tariffs threaten Ireland's low-tax economic model, which relies on huge US investment.
"It's my hope that we will have polling day in this country on the 29th of November and I'm looking forward to the weeks ahead and asking the people of Ireland for a mandate," Harris told RTE News, saying he will seek the dissolution of parliament on Friday to start the campaign.
Sinn Fein's ambition to prevent an unprecedented fourth successive term for Fine Gael looked probable a year ago but the opposition party's support has collapsed over the last year and been further hit by a string of internal controversies.
An average of the most recent polls put Fine Gael on 24.5 per cent, its main coalition partners Fianna Fail on 21.5 per cent and Sinn Fein on 18.5 per cent, according to the Irish Polling Indicator.
Sinn Fein was polling at 35 per cent as recently as a year ago.
Harris has strengthened Fine Gael's lead since he replaced Leo Varadkar in April but faces frustration over unaffordable housing costs, under-resourced state services and concerns over migration.
He must also convince voters he can handle Trump.
Polling suggests Sinn Fein has been caught between its traditional working-class voters who are more sceptical about immigration and newer younger middle-class supporters, shedding support among both groups.
The party that was once the political wing of the Irish Republican Army has long sought a referendum on unifying with Northern Ireland, the region of the United Kingdom where it is already the lead party.
But it would likely need to finish well ahead of rivals Fine Gael and Fianna Fail to cut off their path to re-election, since both have pledged to govern together again without it.
Polling suggests the two parties, former rivals who have between them been part of every government for a century, could reach a majority with current junior partners the Green Party or another small progressive party.
Such a coalition would likely entail few major policy shifts.
