The UHM and the Mepa Professional Workers' Union said today that they were ready to suspend directives issued to workers not to go to Hexagon House once a new ventilation system is in place.
If it was found that symptoms suffered by the workers had stopped, the directives would be withdrawn.
The unions were reacting to a judicial protest by Mepa, which yesterday called on the workers to return to their offices by tomorrow, or else they would be considered as absent.
The workers had been directed by the unions not to work from Hexagon House because of bad smells which, they feared, could be harmful to health.
Mepa said an independent expert had established that there were no hazards to the workers.
The unions expressed solidarity with workers who had suffered health symptoms and for now being threatened for obeying directives after 'nothing was done' to tackle the causes of the problem.