Mark McGowan never needs a second invitation to lay bare his absolute disdain for the Maritime Union of Australia (MUA).

"Its members were bullying, they were threatening and they were un-Australian," the WA Premier told Parliament this week.

"I was shocked and appalled by some of their conduct … I find this behaviour completely and utterly disgraceful."

The comments were prompted by ugly scenes at a community meeting to discuss the McGowan Government's contentious plans for an outer harbour port, which MUA members repeatedly interrupted with heckling and yelling.

The Government has ruled out expanding Fremantle Port and wants to press ahead with a contentious outer harbour port. ( ABC News: Giulio Saggin )

Mr McGowan was far from alone in his fierce condemnation of the MUA and its vocal leader Christy Cain.

"The MUA are a menace to good process, a menace to good government and a menace to the economy of Western Australia," Treasurer Ben Wyatt said.

Transport Minister Rita Saffioti and Ports Minister Alannah MacTiernan also expressed their disgust, labelling the union's conduct "disgraceful" and "ridiculous".

"They are not doing themselves any favours with the way they are conducting themselves," Ms MacTiernan said.

The elephant in the room

But as real as that ill-feeling is, there is an elephant in the room that few people seem keen to publicly address.

The MUA, the same organisation dubbed a "disgrace" and a "menace to the WA economy", still has a powerful role within the Labor Party.

Its boss, Mr Cain, is a delegate on WA Labor's state executive — a body which has substantial influence over the party.

Many senior Labor MPs have joined the Premier in condemning MUA national president Christy Cain. ( AAP: Lukas Coch )

MUA members pay dues to Labor every year, money that goes towards keeping the McGowan Government in power, while the union has donated an additional $135,000 to the WA party's coffers over the past five years.

The MUA also has some influence in the selection of candidates to run for Labor in state and federal elections.

But the question of whether it is time for WA Labor to sever ties is one that very few Government figures are interested in publicly weighing in on.

Ms MacTiernan went closest this week when she suggested the MUA's position in Labor may not be permanent.

"I don't know how sustainable their position is, given their conduct," she said.

But other fierce MUA critics were steering well clear.

"I will let the party deal with that," Mr Wyatt said, while Ms Saffioti also chose not to weigh in on that question.

Privately, plenty of powerful people within WA Labor would love to see the back of the MUA.

The conduct of MUA figures at Labor's state conference last month, an event plagued by walkouts and bitter in-fighting, has left a deeply sour taste even in the mouths of members of the same faction.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 57 seconds 57 s Labor delegates walk out of the WA ALP's state conference

The fact the union is so fiercely campaigning against a core McGowan Government policy, to build a new container port in Kwinana, has not helped matters either.

But even the MUA's harshest critics concede there would be significant obstacles to overcome if Labor were to cut the cord with the militant union.

A costly divorce

Any move to disaffiliate the MUA would likely spark a fierce backlash from some other unions, particularly the Construction, Forestry, Mining and Energy Union (CFMEU), which has officially merged with the wharfies, but still mostly operates separately in WA.

There would also be the financial impact of lost donations and members fees, the fact the MUA could switch its support to a rival political party and the possibility of an enemy emboldened by any move to sever ties.

The difficulties are sufficient that some within the party wonder whether it would be worth the fight.

The MUA has deep ties to the Labor Party in WA which would be hard to unpick. ( ABC News: Samia O'Keefe )

But others insist it is doable and want to see it happen.

"I think people have had enough and are pushing for a divorce," one Government staffer said this week.

The odds of a bloodless, clean separation are likely slim to none, but the stronger Mr McGowan and his ministers are in their condemnations, the more questions are sure to be raised about whether the WA Labor–MUA marriage is untenable.