The maritime union has hit back at Troy Buswell over "inflammatory" claims about their pay dispute with Fremantle Ports as a strike crippling an industrial port in Kwinana enters its fourth day.
Mr Buswell indicated on 6PR on Tuesday the union wanted a 20 per cent pay rise and four day on, six day off rosters.
"These sorts of demands - they're on a different planet," he told the commercial station.
But MUA WA assistant secretary Will Tracey told The West Australian a four on six off roster claim in addition to the 20 per cent pay claim had been taken off the table more than six months ago.
"Those two haven't been talked about in the same breath for quite some time, and have never ever been in consideration in relation to the taking of this action," he said.
MUA assistant national secretary Ian Bray said the minister has misrepresented the union's claims in the media and "politicised" a legal negotiation over pay and conditions between workers and port management.
"For Minister Buswell, a senior minister in the West Australian Government, to get basic facts incorrect about workers' conditions indicates either incompetence or a decision to misrepresent the truth," he said in a statement yesterday.
But Mr Buswell was standing firm on his comments saying the advice he received from the port was the six on, four off rosters were only taken off the table by the union on Wednesday, and employees were seeking a 12 to 20 per cent pay increase in addition to roster changes.
He said his advice from the port was the roster change alone would have added 27 per cent to the cost of operating those aspects of the port.
"That is not an acceptable increase in operating cost for the port," he said.
"I have no reason to dispute the port's facts, they are involved in the day to day operation of the port, the taxpayers own the port, and I am not going to simply stand by meekly and let the MUA ride roughshod over the port of Fremantle," he said.
A Port Authority spokeswoman said the union had asked for increases of more than 20 per cent as well as four on six off rosters for Stevedores at the port, and that only changed on Wednesday when a new deal was offered by the union.
The union is on strike after 11 months of negotiations over an enterprise bargaining agreement failed to reach a consensus, and have blockaded the Kwinana Bulk Handling facility in an action the port says threatens to disrupt up to $300 million worth of cargo movements.
Negotiations between port officials and the union were expected to continue today.