Bun Chiv, a deputy chief customs officer, said the elephant tusks were seized at Sihanoukville port, the country's main port.
He said authorities were investigating whether Cambodia was the destination for the cargo or a transit point, and whether it had come from Africa as suspected, partly because of the large quantity.
"This is the largest amount of ivory ever seized in Cambodia," he said.
Almost all trade in ivory is banned under international agreements. The seizure comes at a time of increased focus on illegal wildlife trafficking.
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The containers had come from Malaysia, but it was not immediately clear what their point of origin or final destination were, it said.
It was the third ivory seizure this year in Cambodia, which authorities believe is a transit point for Asia's major ivory destinations, including China and Vietnam.
The illegal ivory trade has more than doubled since 2007, according to CITES, the international body that monitors endangered species.
In 2012, an estimated 22,000 African elephants were poached for their tusks, according to a study prepared by CITES and other conservation groups.