In January BHP stopped using the last two locally-crewed ships - the Mariloula and the Lowlands Brilliance - to carry iron ore from its base in Port Hedland to BlueScope's Port Kembla steelworks.

Workers on the Mariloula were told of the decision while still at sea.

A worker on the Mariloula, Andrew Richmond, took the ship's contractor Teekay Shipping to the Fair Work Commission over claims he was unfairly dismissed.

Mr Richmond was a casual chief caterer who last served on the Mariloula from June 9 to September 29.

The contractor contended that he was not covered by unfair dismissal legislation as he had not served the minimum employment period of six months.

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Mr Richmond said he had his first "swing" - the roster period between when the ship left and when it finished the route - from December 8, 2017 to March 5, 2018.

His second swing started on June 9 and, after finishing on September 29, he said he was told by Teekay that he would be back on board in late January.

However, the shipping contracts were cancelled earlier that month.

He added that he felt he was "on leave" in between each swing.

A representative for Teekay said Mr Richmond's two swings constituted two separate periods of employment and that, as a casual, his employment was terminated at the end of each swing and all his entitlements were paid.

"The employment was not on a regular and systematic basis because each period of employment was of differing duration and discrete in nature," according to the Fair Work Commission documents.

Commission Deputy President Lyndall Dean said there was clear evidence Mr Richmond's employment "was terminated at the end of each swing".

She dismissed Mr Richmond's application because his latest swing was less than six months and also because it was filed outside the 21-day time limit to lodge applications.