A series of labour disputes at key ports worldwide is threatening to increase congestion in a booming boxship market.

Charter and box rates are already at record highs for some vessel sizes as demand surges amid an imbalance of empty boxes between Asia and the West and delays from the 20,388-teu Ever Given (built 2008) grounding in the Suez Canal.

Truckers at Los Angeles and Long Beach in California walked out on Monday in a row over alleged labour law violations by Universal Logistics Holdings-affiliated companies.

The Teamsters Union said a number of drivers were illegally fired.

Truckers organised a picket line outside ULH's Southern Counties Express trucking yard, in a demand for back pay and union recognition.

The action comes after the National Labor Relations Board issued a complaint against numerous ULH-affiliated companies, finding more than 20 violations of federal labour law.

Canadian action

In Montreal, dockers started a partial strike on Wednesday.

Longshoremen at eastern Canada’s biggest port will work regular shifts from Monday to Friday without overtime hours, and will not work weekends.

The action is related to a contract dispute.

Port capacity is now expected to drop 30%, according to a statement by Montreal Port Authority chief executive Martin Imbleau.

Montreal took three months to get back to normal after a strike in 2020, Chamber of Commerce president Michel Leblanc told reporters.

"It's a decision that’s irresponsible. A port cannot operate part-time," he added.

Some companies have already redirected shipments to the port of Halifax, which is costing them as much as $800,000 per week, Quebec Manufacturers and Exporters Association president Veronique Proulx said at a press conference.

Auckland hit by safety row

In New Zealand, Auckland port workers have walked out to cast a vote of no confidence in senior management and the company's board, Radio New Zealand reported.

A meeting on Tuesday put more pressure on Ports of Auckland chief executive Tony Gibson.

This row is centred on safety at work, following three deaths at the port and a critical health and safety review.

Maritime Union Auckland branch secretary Russell Mayn said on television programme Checkpoint: "It's now three weeks [since the review's release], I thought that perhaps we may have been contacted [by management]."

Port of Auckland communications manager Matt Ball said the port would not be making any comment.