A National Assembly Committee has warned that lengthy delays, tailbacks and disruption to freight supply chains could become the norm without proper planning in Welsh ports following Britain's exit from the European Union.
The report from the External Affairs and Additional Legislation Committee says that many Welsh ports currently lack the infrastructure and physical capacity to accommodate new border controls and custom checks.
The committee has also criticised Economy Secretary Ken Skates for being slow to seek meetings with European counterparts on the issue.
The Welsh Government says that in their White Paper, Securing Wales' Future they have set out their priorities for Brexit which includes avoiding disruption to trade.