MSC said it was prepared to divert ships away from affected Maersk terminals.

"We are working together to find other means to transmit data between the two companies. This includes ... customs information," MSC said in a statement, adding that it had not experienced any cyber attack on its own operations.

Maersk and MSC are the world’s top two container shipping lines.

(Reporting by Jonathan Saul; editing by Jason Neely)