Australian stevedoring firm DP World locked out for 24 hours on Thursday striking Adelaide port workers.

Over the weekend, 140 workers started their industrial action which caused ships to skip Adelaide because the vessel could not be processed or had their international schedule affected.

The strike is the result of an impasse between DP World and the Maritime Union of Australia which had been discussing the pay and work conditions of port employees for the past eight months. The workers are seeking an annual pay rise of 5 per cent. They also aired concern over work safety and the hiring of more casual workers.

Warren Smith, assistant national secretary of the union, said that the casual workers are handling as much or more than their permanent employees. He added DP World has capacity to make the casual workers permanent and the union is pushing for the change of their employment status.

Vincent Tremaine, chief executive of Finders Ports which owns a 40 per cent stake in DP World operations, said that because of the industrial action importers and exporters in South Australia are suffering from slower processing of documents or could instead send their containers by rail to Melbourne which is a more expensive option.

"I think this may be a bit of an attempt to replicate what happened to Qantas and try and create the circumstances where bargaining is removed from the hands of the parties involved.... We reject that entirely. We believe we can reach agreement and we'll be meeting with DP World this week," Mr Tremaine told ABC.

Federal Workplace Relations Minister Bill Shorten said unlike in 2011, he would not intervene this time in the industrial row between DP World and the union. He pointed out that no one at the current stage has indicated they want arbitration so he would leave the two parties to negotiate.

"I'm not going to micro-manage every negotiation that goes on. I know that the negotiations which have disputes attract more media attention than the far greater number of negotiations which go on without disputation," Mr Shorten told ABC Radio.