More than 50 bulkers are waiting to load coal due to a dispute over fees at Australian ports.
Logistics company Transcoal said 36 ships are stuck at Dalrymple Bay, four at Hay Point near Mackay, 10 at Abbot Point and two at Gladstone in Central Queensland.
IHS Markit said another 33 vessels were scheduled to arrive at Dalrymple Bay in the first half of September.
The queues are the result of a row over how much rail company Aurizon can charge Australian coal producers, the Financial Review reported.
A judicial review is due in October into the Queensland Competition Authority's (QCA) decision to strip AUD 1bn ($718m) of revenue from Aurizon's coal network.
Aurizon says the QCA move will see 20m tonnes less coal being exported per year.
BHP Billiton, Rio Tinto, Glencore and Anglo American have threatened to halt production because of the slowdown of capacity on the rail network.
