Ships trying to enter the port of Honolulu have been told to turn around, and any vessels now in the port are advised to leave ahead of a potential tsunami aimed at Hawaii, Chief Petty Officer Chad Saylor, a Coast Guard spokesman, told FoxNews.com.
They are clearing out the port so that emergency supplies and assistance will be able to easily get into the state if necessary.
The Coast Guard has made contact with all large vessels in the area, including a cruise ship, to let them know about the advisory.
The cruise ship was reported to have been refueling and was planning to depart before 6 a.m. (11 a.m. ET).
The Coast Guard also is in touch with local marinas to advise recreational boaters to be safe and secure their vessels.
It is important for an island state to keep its port open in the event of a natural disaster so that emergency supplies and services are able to effectively enter the state, Saylor said.
He could not comment on whether it was safer for ships to be out at sea than in the port.
Click for coverage from KHON-TV in Honolulu.
FoxNews.com's Ali Reed contributed to this report.