The import restrictions on Ukrainian grain maintained independently by Poland, Hungary and Slovakia are probably not compatible with EU law, according to German Agriculture Minister Cem Özdemir, reported dpa.
Özdemir, a Green Party politician, said ahead of a meeting with other EU agriculture ministers in Brussels on Monday that he sees no reason for such measures.
"I also don't see how this can be brought into line with EU law," he added, saying his information showed that the market was handling Ukrainian grain well.
The European Commission is currently analyzing measures taken by the three EU states, a spokeswoman said.
The European Commission had announced on Friday that it was phasing out controversial trade restrictions on Ukrainian grain products. In doing so, the authority opposed demands from EU states such as Poland and Hungary.
In response, Hungary and Poland together with Slovakia announced that they would maintain the measures even without Brussels' approval, saying they need to protect domestic farmers from competition from significantly increased imports from Ukraine.
Ukraine is a major grain producer but struggles to export the foods due to Russia's blockade of Ukraine's Black Sea ports.
Özdemir has the backing of his Spanish ministerial colleague. Unilateral measures that restrict access to the EU internal market do not seem to him to be something that would fall under the law, said Luis Planas.
Spain currently holds the six-monthly rotating presidency among EU states. Both Özdemir and Planas stressed, however, that it is up to the European Commission to judge whether it sees a breach of law in the actions of the three eastern EU states.
Theoretically, the commission can then initiate so-called infringement proceedings, which can end with proceedings before the European Court of Justice and a fine.