A war of words erupted after Sinn Fein MLA Phil Flanagan publicly attacked Mairia Cahill over an article she wrote about the links between the party and the IRA.
In 'Sinn Fein Denials Have Made Fools of the Irish People', Ms Cahill suggested a public inquiry was needed.
She added this could include a cross-examination of Gerry Adams, compelling him to give evidence.
However, Fermanagh and South Tyrone Sinn Fein MLA Phil Flanagan took to Twitter to deride the article and attack its author.
He said: "Some irony in @mairiac31 arguing that a cross-examination in court is needed to get to the truth."
Ms Cahill and many of her followers on the social media site took offence and a war of words erupted.
She told the Belfast Telegraph: "I, like others, was appalled at this crass remark, and I challenged Phil, adding that I would be reporting him to Assembly standards and referred him to the Starmer report.
"His response fell far below the levels of acceptability for an elected representative."
Mr Flanagan responded: "Good for you. Sure write about it in next week's Sindo (Sunday Independent newspaper) too sure."
Later, he issued an apology via Twitter, writing: "I'm sorry if my tweet earlier caused any upset or offence. This was not my intention & I apologise."
But Ms Cahill said: "Comments like Phil Flanagan's are not only distasteful and unhelpful, but they have the potential to scare off victims in coming forward with their abuse, because they will see how others are being treated when they do, and I am not standing for that."
Included in the many respondents on Twitter was the Irish Minister of State for Equality, Aodhan O Riordain, who tweeted: "Pretty disgusting comment from a public representative. The mask slips. Again.
"Really don't want to get involved in mud-slinging over serious NI crisis. But for MLA to publicly ridicule an abuse survivor is disgusting."
It is not the first time that Mr Flanagan has had to say sorry over comments he has made.
In February, he had to apologise to the Assembly Speaker Mitchel McLaughlin for comments he made during a debate about the use of the Union flag on driving licences in Northern Ireland.
Mr Flanagan also came under fire in early August following remarks on Twitter suggesting that sectarian motives influenced roadworks carried out by Transport NI in Kesh and Clabby.
And he was also forced to apologise in 2013 after he shared an offensive tweet regarding the birth of the first child of the Duke and Duchess of Cambridge.