The Sinn Féin leader has apologised after a member of her party reTweeted an offensive post about an IRA murder victim.

Mary Lou McDonald told Newstalk Breakfast that disrespecting victims of the Troubles is utterly unacceptable in her party.

She was speaking after the suspension of Sinn Féin Senator Máire Devine who reTweeted a post describing IRA murder victim Brian Stack as a 'sadist prison officer.'

Deputy McDonald said she has apologised to the Stack family over the incident, adding that she is willing to restate that apology in any way necessary:

“The last thing I want to see is the Stack family, or any other family, upset and discommoded,” she said.

“Certainly my apology is full and I will re-state that apology in whatever format meets with the needs of the family and to demonstrate my bona fides and the bona fides of my party in that regard.”

In a statement last night, Sinn Féin said Senator Devine would be suspended form the party for three months due to her “unacceptable twitter activity.”

The party said: There can be no excuse for the hurt and offence which has been caused to the Stack family.”

However, Labour Party leader Brendan Howlin has claimed that the incident extinguishes any hope that the new Sinn Féin leadership will herald a new dawn for the party.

He said the three month suspension is not enough:

“It seems to be the standard response now of Sinn Féin is to suspend the individual member for three months,” he said.

“[It is] an ineffectual sanction; rather than simply saying very clearly that such commentary insulting victims of former Ira atrocities is wholly and entirely unacceptable.”

Mr Stack’s son Austin has called for Sinn Féin to immediately expel Senator Devine from the party over the tweet.