To keep pace with the workload new, bigger container vessels, typically worth $60 million to $100m each, were being launched from shipyards in South Korea, Japan and China at increasing rates.

But by 2009, when an estimated 11.6m gross tonnes of new container shipping was completed, demand for container space had slipped to 10pc below the previous year, forcing many ship owners to defer taking delivery of new vessels or effectively put existing ships in mothballs.

As export activity declined almost 12pc of the world's container ships (about 570) were "idled" at ports.

Although demand for container shipping revived last year, prompting liner operators to believe the worst was over, the continuing supply of new vessels ordered with shipyards several years ago continued to swamp the market, while demand for containers remains sluggish.

Shipping's bunker fuel costs have also spiraled about 35pc this year from around $US410 a tonne in July 2010, to the sort of peaks seen before the GFC - $US660-plus.

Shipping Australia's chief executive officer Llew Russell said fuel was a particularly nasty cost if your vessel needed pick up speed to make up travelling time after being delayed in port - a common problem in Australian waters.

He said just nine of the 25 container shipping companies servicing Australia were spending an extra $150m a year pushing their vessels harder to get back on schedule after delays at Sydney or Melbourne (which handle 66pc of Australian container traffic).

Mr Russell said some of port inefficiencies and "rorts" by dock workers were now as bad as in the year prior to the explosive 1998 waterside dispute when the National Farmers Federation helped recruit a non-union workforce to replace up to 1400 employees sacked by Patrick Stevedores.

However, while container ship margins were a big worry at present, he said past downturns in shipping activity had turned around "surprisingly quickly" and were likely to do so again once consumer confidence showed even a modest revival.

"And if the Australian dollar drops a bit it will make export activity a lot more attractive," he said.