A Sinn Féin politician has resigned from the Seanad on health grounds.
Niall Ó Donnghaile said he has been unable to attend the Seanad on the advice of his doctor since the summer recess.
His departure will cause a Seanad by-election.
The Seanad has to agree to a motion to fill the vacancy left by a resignation.
When the motion is moved the Minister for Housing Darragh O'Brien has six months to hold a Seand by-election.
It will be the second by-election facing the upper house following the decision of long-standing senator David Norris to resign in recent weeks.
The electorate at a by-election is composed of the members of the Dáil and Seanad, 220 in all.
Mr Ó Donnghaile has been Mayor of Belfast and a councillor representing the Short Strand area of the city in the past.
On his resignation, Mr Ó Donnghaile said: "I feel the best decision for myself, my family and the party going forward is to resign from the Seanad and step back from public life."
"I want to thank those who have supported me over the years and to my family and friends, particularly in the Short Strand, and to my party colleagues for their support during my time in frontline politics," he added.
Sinn Féin leader Mary Lou McDonald said: "Niall has served in the Seanad for almost eight years giving voice to northern nationalists in the Oireachtas.
"I hope that Niall can overcome the health challenges that he has had to deal with over the past number of months, and I wish him and his family the very best for the future."
