Employees of Fremantle walked off their jobs on Friday dawn as scheduled as part of their move to improve working conditions and seek a 6 per cent salary increase over the next three years.

However, despite their 48-hour strike which would last until 5 a.m. of Sunday, Fremantle Port Chief Executive Chris Leatt-Hayter said the 34 vessel movements scheduled within the 48-hour strike period would be maintained.

"We have been very concerned to do all possible with the resources available to us to minimise the impacts on importers, exporters, shipping lines and the community," Mr Leatt-Hayter told The Australian.

However, not all port workers joined in the industrial action. The Australian reports that five of the 23 pilot crew and controllers continued to report for work. Will Tracey, the spokesman of the striking employees said he is disappointed with the decision by some workers to break ranks, although he understands where they are coming from.

"But it's been a really hard decision for these guys to go on strike. You're talking about people who have got careers with the port authority for up to 30 years... this is the first industrial action they've taken," Mr Tracey said.

He pointed out that the port workers earned an average of $85,000 annually which is 30 per cent less compared to their counterparts in other Australian states.

Ahead of the scheduled strike, a few workers walked off their jobs on Thursday, but it resulted in a one-hour delay only in the departure of a container vessel and another hour delay in the arrival of another container ship.

Western Australia Transport Minister Troy Buswell had warned that the strikes could cause the loss of up to $3 million hourly on the state's economy. He wrote to Prime Minister Julia Gillard for the Labor government to directly intervene, but was told to bring the labor row to Fair Work Australia.

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