Brussels is scrambling to find a solution after Poland, Hungary and Slovakia banned imports of Ukrainian grain and other food products, blaming them for driving down prices.

Ukraine's grain exports have been transiting through the European Union to other countries since the war-torn nation's traditional Black Sea routes were blocked by Russia's invasion.

But, because of logistical issues, the grain had been piling up and pushing prices lower, triggering protests from local farmers, who also raised food safety concerns.

Warsaw struck a deal with Kyiv on Tuesday to allow Ukrainian grain to transit again through Poland.

Polish Agriculture Minister Robert Telus said "mechanisms" had been put in place to make sure no grain would remain in his country.

A spokeswoman for von der Leyen said the EU chief had put forward a new 100 million euro ($110 million) package for the hardest hit farmers in a letter to five eastern European governments.

That money would come on top of 56 million euro package that was provided for farmers in Poland, Romania and Bulgaria last month.

Von der Leyen also proposed taking "preventive measures under the applicable trade rules" in regard to certain grains such as sunflower and rapeseed, spokeswoman Dana Spinant said.

Brussels has previously insisted that any unilateral bans on the Ukrainian exports were "not acceptable" and noted that trade policy is solely an EU responsibility.

EU trade commissioner Valdis Dombrovskis is to meet later on Wednesday with representatives from Poland, Slovakia, Hungary, Romania, Bulgaria and Ukraine to discuss the proposals.

The EU standoff has come as tensions over a deal with Russia to allow grain out of Ukraine via the Black Sea has again fuelled fears for exports.