Dublin South-West TD Paul Murphy has left the Socialist Party.
Mr Murphy says he made the decision after "extensive debate" within the party.
"A number of members including me decided to leave and launch a new group", he adds.
There is a call for an emergency rent freeze for at least three years to tackle the housing crisis.
It comes as Carlow and Macroom have become the two latest areas to be designated as Rent Pressure Zones (RPZs).
While the Residential Tenancies Board's latest index shows a 7% annual increase in national rents.
The US House Intelligence Committee has published a whistleblower letter, which claims the White House tried to “lock down” records of President Donald Trump’s call with his Ukrainian counterpart.
It comes as Mr Trump urged Ukrainian President Volodymyr Zelenskiy to work with his lawyer Rudy Giuliani and the US attorney-general to investigate Joe Biden.
In the newly-published letter, an unamed official says: "In the course of my official duties, I have received information from multiple US government officials that the president of the United States is using the power of his office to solicit interference from a foreign country in the 2020 US election".
The President Michael D Higgins has praised former French president Jacques Chirac as "a good friend of Ireland".
Mr Chirac died on Thursday at the age of 86.
His son-in-law Frederic Salat-Baroux says the veteran politician passed away peacefully and "among his loved ones".
The leader of the Green Party in Canada was "shocked" to discover that an image of her holding a disposable cup was photoshopped.
The photograph on the party's website showed Elizabeth May holding a reusable cup displaying the Greens' logo with a metal straw.
However, in the original picture, taken over a year ago at a street market event, Ms May is holding a compostable disposable cup without the straw.