Costello said coal ships were facing delays of up to 23 days through Dalrymple Bay, while coal companies were paying $2.4 million per day in demurrage costs.

The treasurer said 50 ships were waiting off the Queensland coast to be loaded with coal.

But the Queensland Government last night rejected Costello's proposal.

State treasurer Terry Mackenroth said if the ACCC took over from the Queensland Competition Authority in setting tonnage charges, the result would be more delays at Dalrymple Bay.

In addition, an ACCC spokesperson told the Courier Mail yesterday an approach would first have to come from the Queensland Government for it to act.

Costello said a dispute over the rate of return on new investment between the company which runs the port and coal companies had now been with the Queensland Competition Authority for 20 months.

He said the dispute was holding back exports of Australia's most valuable export commodity, and there was scope for the ACCC to intervene.

"The parties can either come to agreements in relation to this matter, which may be a much faster way of resolving the problem, or alternatively, there is provision for a declaration under the Trade Practices Act which will allow the ACCC to intervene in areas of national infrastructure and to make decisions, timely decisions, which can resolve these disputes.

"That may be an alternative to the parties if this matter should drag on any longer in the Queensland jurisdiction in a way which is now affecting Australia's vital national interest and our number one coal export."

The port company would need between 12 and 24 months to build a new loader (the core of the dispute between it and coal miners), which would slash loading times.