Trump among hot topics as Ireland announces election

"The time is now right to ask the Irish people to give a new mandate," Harris told journalists in front of his office on Friday, before departing for the president's residence to seek the formal dissolution of parliament.

The left-wing Sinn Fein's ambition to prevent an unprecedented fourth successive term for Harris' Fine Gael looked probable a year ago, but its support has collapsed over the last year and been further hit by a string of internal controversies.

The campaign should be about who can "credibly" increase much needed housing supply, oversee a fair but firm immigration system, and prepare for a potential transatlantic trade shock from Donald Trump's election as US president that could hit Ireland's finances, Harris said earlier on Friday.

"Our discussion in the weeks ahead does need to broaden. Up until now it's been about how you're going to spend the money available to government," he said.

"Dependent on being able to spend that money is being able to generate it, keep jobs, keep investment and show leadership at an EU level."

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.

Speaking to supporters late on Thursday, Sinn Fein MPs said it was naive to write the party off as they sought to turn the focus to voter frustration over unaffordable housing costs and strained state services.

"Simon Harris and (Fianna Fail leader) Micheal Martin believe that they have it all sewn up. I think the people of Ireland will have something to say about that," Sinn Fein leader Mary Lou McDonald said.

Sinn Fein needs a repeat of its stunning surge during the 2020 election campaign as it likely has to finish well ahead of Fine Gael and Fianna Fail to cut off their path to re-election, since both have pledged to govern together again without it.