"I think it would be in the tens of millions; the bulk of the costs will come from storage charges from the ports and container companies," he said.

"There will be costs associated with people missing out on business; there will be costs for people who have had to work overtime because the system was working slowly.

"There is also likely to be some stress claims because people have worked very long hours in very frustrating circumstances to try and get goods cleared."

Stephen Morris, Customs Brokers & Forwarders Council of Australia chief executive, said there was evidence to show some people were leaving the industry because of the new system.

Morris also said brokers would be less inclined to deal with small importers.