Picketing elevator maintenance workers greeted crews heading in to work at the new courthouse in Thunder Bay on Friday morning.
About 20 local members of the International Union of Elevator Constructors International set up lines around the building currently under construction.
"We're picketing here because it is really the only big construction site in Thunder Bay," said local union representative Graham Renner.
"We have work that's in here that's not getting done. There's been talk there are other people in here doing our work, but we aren’t sure. We don't want to picket here every day. Just once in a while. We get visibility this way."
Renner said most local contractors did not cross the line, slowing work at the south core site.
Out-of-town workers did cross the picket line, however, according to Renner.
The union's deal with the National Elevator and Escalator Association expired at the beginning of May.
Renner said both sides in the dispute are back at the table, with the help of a mediator from the Ministry of Labour.