Brisbane commuters are being told to make alternative arrangements, with ferry drivers set to walk off the job for the second time this month over pay and conditions.
CityCat services will run at a reduced frequency during the 24-hour strike, which begins at 4am on Thursday.
Ferry workers wages have been going backward over the past few years and they're pursuing a fair deal from their employer Transdev, Maritime Union of Australia's Jason Miners told AAP on Wednesday.
"Transdev has not offered a fair deal for these workers," Mr Miners said.
Two weeks ago, the union called a 48-hour strike and he said the action would continue to get an outcome.
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"These workers are resolute and will keep pursing this for the right outcome for as long as it takes," Mr Miners said.
"Over the years they have been treated like garbage so they are willing to stick by one another for as long as it takes."
Transdev Managing Director Tilly Loughborough has apologised for the inconvenience to customers.
She said there was a hearing at the Fair Work Commission scheduled for Thursday.
"It is therefore surprising to receive the notification of intention to take industrial action by the unions."
CityCat services will be running at a reduced frequency on Thursday, and are expectedto be busier than usual.
