The Cook Islands says two of its three flagged ships which have been refused entry to U.S. ports, must comply with a new security code before they will be granted entry.
The Cook Islands registrar of ships, Garth Broadhead, says one is already fully compliant and can present the correct certificates.
But, he says two cargo vessels, which they thought were too small to be covered by the regulations, will have to meet the U.S. requirements.
"They now need to wait outside U.S. waters until such time as they're able to develop, and submit, and have approved a ship's security plan, train their crew in the relevant provisions of that plan. And, then they can seek to re-enter U.S. waters."
Garth Broadhead says the United Nations International Shipping and Ports Facility security code came into force last week.
It requires international ships to have a signed certificate from their flag country, stating they they comply with new standards aimed at foiling terrorists.