Brisbane's ferry workers will stop work for 24 hours on Saturday — the night of Riverfire, the ABC reported on Tuesday. Up to half a million people are expected at the river precincts for the fireworks that open the Brisbane Festival, and about 27,000 of them took a CityCat or ferry to get there last year. This year, the boats stay docked.

The stoppage is the sharpest move yet in a pay dispute that has been running since October last year between the Maritime Union of Australia and RiverCity Ferries, which operates the CityCat and ferry network in partnership with Brisbane City Council. Workers have been taking intermittent industrial action since 30 July; the union says nothing further is planned beyond Saturday.

What each side says

RiverCity Ferries general manager Paul Rigby accused the union of planning to "spoil the party". "We value our hard-working staff and have worked to put a strong offer on the table for them," he said. "But unions are planning to spoil the party and disrupt the plans of tens of thousands of travellers for the sake of their protracted and unreasonable industrial campaign."

MUA organiser Jaiden Simpson denied the union was trying to ruin the night — "we would deny that wholeheartedly" — and said the operator had not meaningfully engaged with the workforce "for the past 17 meetings", a figure that is the union's own count. The claims on the table, he said, run past pay: "Fatigue management, work-life balance, meal break provisions, obviously salary and superannuation are to be addressed, but a range of other conditions RiverCity Ferries has chosen not to address at all."

On the money, the union is seeking a three-year agreement with a six per cent rise in the first year, with later increases yet to be decided. Simpson characterised RiverCity's latest offer as equal to the Fair Work Commission's annual wage increase — his description, not the operator's. "We haven't chosen to do this lightly, and our membership in the union does not want to … proceed with this industrial action," he said. "But ultimately we've been left with no choice."

The council fight on top of the pay fight

Brisbane City Council's public transport chair Andrew Wines called the timing "a stunt designed to cause maximum pain". "Riverfire is one of Brisbane's biggest nights of the year and it's an absolute disgrace the union is planning to mess with it," he said, adding that the union had not given members time to vote on the latest offer. Simpson rejected that account — members voted for the strike, he said, after RiverCity put out an offer last week that the union had not endorsed for a vote opening this weekend. The two versions cannot both be right, and neither side produced documentation in the ABC's report.

Labor's deputy opposition leader on council, Lucy Collier, aimed her criticism at the administration instead: the council had "failed to sort this out" ahead of Riverfire, she said, and workers were paying the price. "Instead of attacking workers, the people of Brisbane just want Brisbane's Lord Mayor to step up and be a leader to get these workers a fair deal and get ferries and CityCats back on the river."

If you were planning to catch a ferry

You will need another way in. No replacement-service plan was described in the ABC's report, so the practical advice is to check TransLink's service updates before Saturday evening and expect the trains, buses and roads around the river precincts to carry the load the ferries usually take. Half a million people and no boats is a squeeze the rest of the network will feel.

However the vote-timing argument resolves, one fact is not in dispute: the negotiations have run for close to a year, the action has escalated for a month, and the deadline that finally concentrated everyone's attention is the city's biggest night on the water.