A PICKET line organised by the Maritime Union brought traffic to a standstill on Friday morning, as unionists prevented workers accessing Alcoa’s Pinjarra refinery.
Traffic was banked up on the Alcoa access road off South West Highway from about 6am with gridlock for as far 10 kilometres.
Police were called to the area.
Maritime Union secretary Chris Cain said the union was protesting Alcoa’s decision to lay off 40 seafarers from the MV Portland, which travels between Victoria and Western Australia.
“We’re highlighting the point that Alcoa are sacking Australian workers to bring in cheap, exploited foreign labour,” he said.
“This ship has gone from Victoria to WA for the last 27 years and what they want is to sack those Western Australians and put foreigners on that job.
“They say because it’s cheaper, they want to get rid of Australians and put on foreigners and exploit them as well.
“We’re fighting for Australian mariners who have a right to work in their own country.
“We’re letting Alcoa know that we’re not going to cop that stuff.”
A spokesman for Alcoa said the company was considering legal options in relation to the incident.
"Alcoa is very disappointed with the union action this morning in mounting a blockade on the private access road to the Pinjarra alumina refinery," he said.
"While production at the refinery was not impacted, night shift workers were prevented from leaving for at least 1.5 hours after the end of their 12-hour shift and traffic was disrupted on both Alcoa’s private road and the South West Highway."
However, Mr Cain said workers were not prevented from leaving.
"We said to shift workers they were welcome to leave, but if they chose to work longer it was their decision, I don’t think anyone should be made to work more than 12-hours," he said.
About union claims in relation to the MV Portland, Alcoa's spokesman said the vessel was being decommissioned because it was nearing the end of its useful life.
"The global aluminium industry is facing very challenging market conditions," he said.
"In Australia, our focus is on reducing operating costs and improving productivity to help all our facilities remain internationally competitive.
"Decommissioning the MV Portland is one of a number of cost saving measures being taken by Alcoa in an attempt to help protect approximately 700 direct jobs and many more indirect jobs associated with the Portland [Victoria] smelter."
He said any replacement vessel would only be chartered from shipping owners who pay their crew the salary required under the International Transport Federation award.