Marine engineers will escalate industrial action aboard a government-owned dredger this week after accusing the Port of Brisbane of using "scab" labour to break legitimate work bans.

The Australian Institute of Marine and Power Engineers (AIMPE) said enterprise agreement talks broke down last week after more than 12 months of negotiations with the crew of the Trailer Suction Hopper Dredge (THSD) Brisbane.

"It is appalling that after more than 12 months of discussions a state Labor government entity fails to negotiate in good faith but sees fit to break legal AIMPE members' work bans by employing a scab subcontractor," AIMPE national organiser Greg Yates said in Brisbane.

"This attempt to nullify AIMPE members' work bans and rights has only thrown fuel on the fire - industrial action will escalate this week."

The engineers will strike once the vessel reaches Cairns on Thursday.

Mr Yates said engineers aboard the Brisbane studied for up to 15 years to achieve their qualifications but are being paid about $50,000 less than the going industry rate of pay.

Mr Yates said the dredger would be sold as part of the state government's plan to privatise publicly-owned ports and the government had delayed negotiations in the hope a new owner would be left to deal with the marine engineers' claim.

Comment is being sought from the Port of Brisbane.