The Government is facing a serious test of its strength in the Dáil after the Social Democrats announced that it will next week table a no-confidence motion in Minister for Housing Eoghan Murphy.
The party will use its private members' time on Tuesday to bring forward a vote.
The move, which has taken the Government by surprise, will give an added significance to Friday's four by-elections.
It also comes amid speculation that Fine Gael TD Dara Murphy is set to resign his seat in the Dáil to take up a job in the European Commission.
Social Democrats Co-Leader Catherine Murphy said "enough was enough" on the housing crisis and Minister Murphy has to resign.
She added that Dáil arithmetic is the least of the party's concerns and that if the motion triggers a general election, so be it.
Ms Murphy said the tone in recent weeks misses public sentiment on the housing crisis.
She said people are not willing to continue suspending their lives by not being able to afford huge rents and that those on good incomes cannot afford to purchase a house.
Ms Murphy said there should be a 'war office' approach to housing.
Co-leader Róisín Shortall said Fianna Fáil needed to decide if it stands on the side of people who are trying to access housing or on the side of Fine Gael.
A spokesperson for Minister Murphy said the motion is an "election stunt" ahead of the by-elections on Friday.
"This is pathetic and the Social Democrats would be better using their time seeking support for a constructive solution rather than a stunt that will not pass," the spokesperson said.
- November by-elections present departure from the norm
- Government believes it has numbers to see off motion
Taoiseach Leo Varadkar said he has 100% confidence in the minister.
Mr Varadkar said more than 20,000 homes have been built this year, which is more than any year in a decade.
He said Minister Murphy needs to get on with the Government's plan of building more houses.
The tabling of the motion will raise serious questions about the Government's working majority particularly if Fine Gael fails to win any of the by-elections.
Today's announcement was also unexpected by Fianna Fáil.
However, that party remains adamant that a general election before Christmas is not a viable option given the lingering Brexit uncertainty.
Additional reporting Aisling Kenny & Maggie Doyle