The Maritime Union of Australia will pay $215,000 in penalties and compensation to workers for putting up posters vilifying them as "scabs" because they refused to take part in a strike at Fremantle.

Following the union losing an appeal on Thursday against a scathing Federal Court judgment, four workers will receive $20,000 compensation each and a fifth worker will receive $40,000 as he was named a scab despite not working during the 2011 strike at the Fremantle Port Authority.