Opposition members walked out of the Dáil chamber over the decision to cancel a debate on a motion setting up an inquiry into incidents in the Cavan-Monaghan Garda Division.

It was cancelled yesterday evening after Ceann Comhairle Sean Barrett told the parties some matters were sub judice.

Taoiseach Enda Kenny told the Dáil this afternoon that the ruling of a Ceann Comhairle was not reversible.

Mr Barrett said the motion could be moved but he ruled that a debate was not allowable on the terms of reference for the commission of investigation.

The inquiry was one of the investigations ordered by the Guerin Commission prompted by allegations made by Sgt Maurice McCabe.

Its findings led to the resignation of then minister for justice Alan Shatter.

It is understood that the Ceann Comhairle's decision to block the debate is linked to a High Court action being taken by Mr Shatter challenging aspects of the Guerin Report.

Fianna Fáil leader Michéal Martin said this afternoon that his party did "not want to participate in a sham" and the House should be adjourned.

He said that the Ceann Comhairle needed to offer an explanation as to what was going on.

Sinn Féin leader Gerry Adams said the debate should be re-ordered. When the Taoiseach asked that the matter go to a vote, opposition TDs walked out.