According to José Manuel Oliveira, coordinator of the Federation of Transport and Communications Unions (Fectrans), the next strike is to start at midnight on 25 June and run to midnight on 26 June.


The announcement came on a day when the metro had come to a halt because of the latest 24-hour strike. Services stopped at 11.20pm on Wednesday and are only due to restart at 6.30am on Friday. According to union officials, participation in the strike was near total.


The metro company does not supply figures for strike participation, but confirmed that all stations were closed.


Portugal's government in February approved moves to subcontract the operation of Lisbon's metro, bus and tram services. On Monday it announced that five candidates had submitted proposals, with three of them being consortiums involving two companies each. They include RATP and Transdev of France and the UK's National Express and Spain's Avanza.


In comments to Lusa earlier this month, the chairman of the new merged Lisbon transport company, Rui Loureiro, said that the contracts should be signed after 15 July.