Sinn Féin is the most scrutinised party in Ireland, according to deputy leader has Mary Lou McDonald.

Ms McDonald said those suggesting Sinn Féin is linked to criminality must produce proof to back the “tired, abusive slurs”.

“We are organised nationally. We are scrutinised North and south. In the North, there is a legal obligation to publish your annual accounts,” she said.

"We also are scrutinised in America by the State Department and let me tell you, that scrutiny is very exacting and that is as it should be. I would suggest that we are the most scrutinised and we have the most oversight."

Ms McDonald said politicians on both sides of the Border were quick to seize on two brutal murders and two grieving families.

She said this was about gaining political advantage and called on those politicians to “take stock” over the coming days.

“Half of the difficulty we face is what do people mean when they talk about structures of the IRA.

"The IRA has gone away but those who were volunteers still exist, they are still around," said the Dublin Central TD.

“What do we do about that? To be blunt with you, my assessment of it and my concern is that people who were previously volunteers who were involved in military campaign are now four square behind the democratic and peace process.

“That is what matters, is it not?”

Fianna Fáil leader Micheál Martin last week accused Sinn Féin of jeopardising the peace process after PSNI chief constable George Hamilton stated that the IRA remains an operational entity, although it no longer systematically engages in terrorist activities.

The PSNI chief constable was giving his assessment of the situation after it was alleged that there was an IRA connection in the murder of Kevin McGuigan in Belfast.