The last three weeks' sittings of the High and Supreme Courts in this law term are threatened by industrial action from clerical staff, due to start next Monday.
Special vacation sittings to deal with issues like bail applications, applications for judicial review and injunctions could also be affected.
The dispute concerns alleged changes in promotions procedures for administrative staff. According to Mr Peter Nolan, an official with the IMPACT trade union which represents those involved, these procedures have been changed by management without negotiation.
Promotions are traditionally on the basis of seniority and suitability, he said. However, the Courts Commission, under the chairmanship of Ms Justice Denham, proposed widespread changes in how the courts were run. This included promotions on the basis of competitive interview, rather than seniority.
"We have no problem with that in principle, but we need to negotiate on it," said Mr Nolan.
Two positions of acting assistant registrar have come up in recent months. One arises from the temporary transfer of an acting registrar to the interim courts service, the other from a jobshare, so the union is not contesting their "acting" status, while negotiating the filling of the posts.
The union had expected the positions to be filled from among the most senior people, who are listed according to seniority.
Mr Nolan told The Irish Times that last week management invited applications from court clerks for these positions. "They have not accepted the most senior people or informed them they are not suitable," he said.
He said they would now be at a disadvantage in a situation of open application. Asked why they would be disadvantaged, he said: "Otherwise they would have been appointed."
Initially the industrial action will involve refusing to do the work of the vacant posts which are the subject of the dispute. This will escalate to refusing to co-operate with information technology, recently introduced into the courts and one of the factors which has helped in clearing the large backlog of cases which has built up over recent years.
The issuing of summonses, for example, is now done with information technology, but will be done manually if the dispute continues. This would delay them considerably, perhaps putting them outside the statute of limitations and thus allowing them to fall. All civil and chancery proceedings will be affected.
This law term runs to the end of July, so there will be three weeks from next Monday for the dispute to delay and disrupt proceedings. The special High Court sittings throughout the vacation, usually held to deal with urgent matters like injunctions and bail applications, could be disrupted by the action.
According to Mr Nolan, the union's mandate from the members includes full industrial action if agreement is not reached.
The Department of Justice had no comment on the dispute yesterday.