The head of the Workplace Relations Commission (WRC) says if any changes are made to the Lansdowne Road Agreement for teachers, then other unions would come back looking for separate deals too.

Kieran Mulvey was responding to threats of industrial unrest by teachers unions that have refused to sign up to the agreement.

The president of the Teachers Union of Ireland (TUI) is again warning of industrial unrest, after the commencement order for the Lansdowne Road Agreement was signed yesterday.

Signing the order, Public Expenditure Minister Brendan Howlin said trade unions who do not sign up to the public sector pay deal will not be entitled to share its benefits when it kicks in next July.

The teaching unions - the ASTI and TUI - and both the Garda Representative Association (GRA) and the Association of Garda Sergeants and Inspectors (AGSI) have rejected the accord.

President of the TUI, Gerry Quinn, says there will be industrial unrest before the election if the Government does not enter talks with them on the deal.

"As sure as night follows day that will happen - because the depth of feeling with regard to these problems in our schools and in colleges and in our Institutes of Technology is very, very real" he said.

"The strategy that we are putting in place is to act before the general election - in order to provide an opportunity for the government to think twice and to talk to us" he added.

He told Newstalk Breakfast teachers are steadfast in their resolve.

But Kieran Mulvey says if any changes are made for teachers, then other unions would quite rightly come back and look for separate deals too.