APM Terminals spokesman Erik Eisenberg said he firm was taking the allegation from a sub-division of the International Longshore and Warehouse Union (ILWU) seriously and was investigating whether there was any truth to it.
"The allegation is that there would have been phone tapping taking place, that management would have listened in to conversations between labour representatives," Eisenberg said.
"We have put the person who is at the centre of these allegations, a manager in our Los Angeles facility, on administrative leave," he said, adding he did not know when the alleged tapping was meant to have taken place.
He did not confirm a report by Danish union 3F's paper Fagbladet3F late on Wednesday that APM Terminals had admitted to the claim to ILWU.
He also declined to say whether the union had filed any legal complaint against APM Terminals. Fagbladet3F reported the union had filed a complaint to a U.S. labour law board.
Port workers at several terminals in the Los Angeles area, including one owned by APM Terminals, returned to work after an eight day strike. (Reuters)
