Update 6.45pm: Sinn Féin have voted not to allow a 'conscience vote' on the issue of abortion.
Following a passionate, hour-long debate the Sinn Féin Ard Fheis passed a motion backing the repeal of the Eighth Amendment and supporting abortion in cases where pregnancy poses a risk to maternal health, including mental health.
The Ard Comhairle motion was slightly amended to say abortion should be available when a woman's health is at risk - instead of serious risk and in grave danger.
The motion sets the party policy for both Northern Ireland and the Republic of Ireland.
A proposal to allow a free vote on abortion was defeated.
The party's Peadar Toibin had urged that party members vote according to their personal beliefs.
"You cannot cherish all the children equally if you do not deliver the equal right to life to all children," Toibin told the Ard Fheis.
"Motion 144 would be the third policy in four years on this, given that so many of us joined under a different policy regime on this, is it not reasonable to offer us some flexibility on this issue?"
At the beginning of the debate Sinn Fein deputy leader Mary Lou McDonald said that the Eighth Amendment on abortion should never have been put in the Irish constitution.
Sinn Fein changed its policy in 2015, when it said women should have access to terminations in cases of fatal foetal abnormality.
The party has previously backed abortion in relation to incidents of sexual crime.
Meanwhile, a tribute to the late Martin McGuinness is currently underway.
Over 2000 people packed into the RDS in Dublin to watch a special tribute to the life & legacy of the late, great giant of Irish republicanism.
Martin McGuinness. pic.twitter.com/X1gOrW4Mg9— Sinn Féin (@sinnfeinireland) November 18, 2017
2,500 delegates give the late, great Martin McGuinness a standing ovation for his contribution to peace and justice on our island. pic.twitter.com/i6vK2Z94P2— Sinn Féin (@sinnfeinireland) November 18, 2017
Update 6.04pm: Sinn Féin’s Ard Fheis is hearing arguments for the 8th Amendment to the Constitution to be repealed.
The motion, proposed by the party leadership, also calls for abortion where a woman’s health or mental health is at risk.
Deputy leader Mary Lou McDonald has called for a repeal of the 8th amendment.
"It is my firm view that the 8th Amendment protects nobody," Ms McDonald said. "It was, and it remains, a deeply cruel amendment to our Constitution that sought primarily to subjugate women and it has no place in the Irish Constitution."
Tonight, Gerry Adams is expected to announce a timetable for his departure as leader and the party will celebrate the life of the late Martin McGuinness.
Update 5.19pm: Sinn Féin have addressed the homelessness crisis at the Ard Fheis today.
The party has said that it would double the social housing spend if it was in Government, to ensure that no child is homeless.
Sinn Féin housing spokesperson Eoin O'Broin told that 10,000 homes are needed each year until the problem is solved.
"Sinn Féin would get a grip on the homelessness crisis so that no child would be in emergency accommodation any longer than is absolutely necessary," Mr O'Broin told the Ard Fheis.
"And we would do all of this while ensuring the highest possible building standards and levels of energy efficiency."
Just some of the stalls at this year’s #SFAF17 - our live feed is online again at 6:30pm today on Facebook, Twitter and sinnfein.ie. pic.twitter.com/KIucabjwFW— Sinn Féin (@sinnfeinireland) November 18, 2017
Sinn Fein has also passed a motion calling for training sessions for councillors.
It’s being widely seen as a response to allegations of bullying by several party councillors, some of whom have left the party.
National Chairman Declan Kearney spoke out against bad behaviour:
"We do not tolerate sectarian, racist, sexist or other discriminatory attitudes or practices," Mr Kearney said.
"Some people join our party for the wrong reasons. Some join and then fall out with others because they don't get their own way."
In recent months, there have been numerous allegations of bullying in Sinn Féin at a local level from across the country.
Several locally elected members have left or been expelled from the party.
Update 3.56pm: Sinn Féin is calling for the establishment of an Oireachtas Committee to examine the possibility of a united Ireland.
The party is holding its largest ever Ard Fheis in Dublin, where it has been discussing housing, the Irish language and climate change.
Later, party President Gerry Adams is expected to set out a timeline for his eventual departure.
Pearse Doherty wants politicians in the Dáil to consider the possibility of a united Ireland.
"All of us who say we want a united Ireland must work for that united Ireland and an all-party Oireachtas Committee on Irish unity is the logical next step," Mr Doherty said.
"So I ask Leo Varadkar and Micheál Martin, what have you to fear of an Oireachtas Committee on Irish unity?"
Sinn Féin has set its sights on entering government – even as a junior coalition partner.
The party voted to reverse its earlier position on not being the smaller party in a coalition.
But both Fianna Fáil and Fine Gael have ruled out going into government with Sinn Féin.
Deputy leader Mary-Lou McDonald took a pop at the Taoiseach in her keynote speech at the RDS this morning.
"Our new Taoiseach Leo Varadkar is some craic," Ms McDonald said. "He is a Taoiseach that tries to deny and minimise the scale of this emergency.
"The same Taoiseach fights the corner of coporate tax avoidance.
"Now this Taoiseach, my friends, says that I’m cranky. Leo, you haven’t seen cranky."
Among the motions being debated at the Ard Fheis today is campaigning for the Repeal of the 8th amendment.
Several motions suggest allowing members to vote according to their conscience, unlike the present rule.
However, Ms McDonald says members should vote as one.
"We understand that it is not credible for a political party not to have a position on an issue such as this. Which is an issue of public policy, it is a matter of public health and women’s health.
"The objective of the Ard Fheis is to debate the motions in front of us and arrive at a considered, collective position that is how Sinn Féin policy is made."