Some 30 containerships are without a berth in the Antwerp region, following a 24-hour walkout by the Flemish Pilotage Service union.
The strike commenced at 7 pm on Monday. Sources said on Tuesday that about 40 vessels were then outside Antwerp, unable to discharge or load.
Due to the backlog, the source said, there is now an "acute” lack of pilots to handle vessels waiting to berth.
In response, ultra-large container vessels reportedly did not wait, the lines opting to divert their vessels to Rotterdam, before rerouting boxes on barges back to Antwerp by inland waterways.
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