Pickets were placed yesterday on two building sites operated by Collen Construction in support of three bricklayers who were jailed last week.
Andrew Clarke, Cromlech Fields, Ballybrack; Keith Kelly, Ashlawn Park, Ballybrack; and William McClurg, Sallynoggin, have been in Mountjoy Prison since Friday.
They were jailed for failing to obey a High Court order to stop picketing a Collen site in Ballybrack, Dublin. They claimed they were refused jobs there because they are active members of the trade union, Batu.
Supporters of the men picketed Collen sites yesterday at UCD and the Hugh Lane Municipal Gallery at Parnell Square.
The firm said afterwards that a protester had threatened an employee at the Parnell Square site with a knife and the matter had been referred to the Garda. A Garda spokesman said a complaint had been received and an incident was being investigated.
Richard Boyd Barrett, involved in organising the pickets, said no such incident had been drawn to his attention and protest organisers would not condone it.
Collen Construction also said Batu had rejected a "draft agreement" to end the dispute. A Batu representative could not be contacted but Mr Boyd Barrett said the proposals had offered nothing substantive.
