The measures, which Congress has demanded must enter force in 2012, will oblige countries to scan every one of the estimated 18 million US-bound cargo containers each year before they leave their port of departure.
"We believe strongly that those costs would be added to the supply chain," Jayson Ahern, deputy commissioner at US customs and border protection, told reporters in Brussels.
More than three quarters of the world's trade, in terms of volume or weight, is moved by sea.
Customs experts have calculated that even if enough containers are checked to make the move efficient -- at least 200,000 -- it could add around a billion dollars annually (640 million euros) by the time the laws come into effect.
"That's ultimately being passed onto the consumer, and that's unfortunate," Ahern said.
"Consumers in our country certainly realise that security comes at some cost but at what point is it really unnecessary?
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"I don't think this is a wise use of US taxpayers' money," he s