The Labour Court is intervening in an attempt to end the strike at the nation's National Car Testing (NCT) centres.
The row over pay has led to the closure of NCT centres in Dublin for three weeks and across the country for the last week.
The tax office has had to give motorists three months grace because of the strike.
SIPTU's John Kane has welcomed the Labour Court move.
"The problem is wages, working hours, rosters, health and safety. There is a whole range of issues outstanding over the last six to eight months which have yet to be resolved," said Mr Kane.