The EU on 2 May set restrictions until 5 June on imports of Ukrainian wheat, maize, rapeseed and sunflower seed to ease the excess supply of the grains in Bulgaria, Hungary, Poland, Romania and Slovakia.
Those countries had complained that cheaper Ukrainian grain was making domestic production unprofitable and had asked the EU to extend the ban.
"We have received from the EC a draft of a new regulation banning the import of four products to the five countries," Robert Telus wrote on Twitter. "The effective date provided for in the draft is 15 September this year."
"It's a draft but I hope it will come into force from tomorrow," he added.
A European Commission spokesperson did not immediately respond to an emailed request for comment.
Ukrainian wheat, maize, rapeseed and sunflower seed can be sold to any other country in the 27-nation bloc.
The EU had earlier liberalised all imports from Ukraine to help Kyiv's efforts to fend off Russia's invasion. The five countries became transit routes for Ukrainian grain that could not be exported through its Black Sea ports because the war.
Ukrainian President Volodymyr Zelenskiy on Thursday called for the unconditional removal of all export restrictions on Ukrainian agricultural products at talks with European Commission president Ursula von der Leyen.