Containers of fish are stacking up at European ports after a new digital system designed to flag illegal catches buckled under pressure, triggering warnings of severe issues for the industry and looming shortages.

At a meeting on Monday of European Union fishing ministers, representatives from seven countries said parts of the platform launched this month were unworkable, according to a report in the Financial Times newspaper.

Seafood importers, who have been bogged down with the tasks demanded by the system, are calling for a grace period.

Italy's representative said at the meeting that the system "risks paralyzing our imports and the logistics of our companies", while Estonia likewise flagged issues, reported the FT.

Launched on Jan 10, CATCH obliges importers to manually input hundreds of entries pulled from vessel certificates that attest to compliance with EU rules.

According to the European Commission, CATCH replaces the old paper-based process and standardizes and harmonizes import controls for fishery products across the EU.

One importer said it had dozens of shipping containers stuck at Rotterdam port in the Netherlands because the system is clearing only about half of the consignments. The person told the FT that responsible authorities were not responding to requests for assistance.

Beyond data entry, which can take several hours, importers from countries without digital records must also upload the catch certificate, the person said. They added: "The upload limit is 2 megabytes. We have 80-page catch certificates. They are much bigger than 2MB."

EU member states said skippers must count fish caught in mixed batches while trying to navigate, which can lead to mistakes and fines.

In a submission to the meeting, they said "the strict application of these rules will lead to an increase in unintentional infringements, not due to fraud, but due to the material impossibility of complying with excessively detailed requirements under real fishing conditions".

Seafood Europe urged a six month transition, while its president, Guus Pastoor, warned: "Delays will certainly cause deterioration of the quality of fresh fish."

A commission official said there was "no evidence" the system is blocking imports, citing 3,530 declarations, and noting temporary "flexibilities" were allowed.