Kyiv has urged Poland to punish those responsible for spills of a Ukrainian grain cargo at the border over the weekend, Deputy Prime Minister Oleksandr Kubrakov said on Monday.

Around 160 tonnes of Ukrainian grain were destroyed at a Polish railway station amid protests in what a senior Ukrainian official said on Sunday was an act of "impunity and irresponsibility".

"Those who have damaged Ukrainian grain must be found, neutralized, and punished. Two friendly civilized European states are interested in this," Kubrakov said on X.

Polish farmers protesting over what they describe as unfair competition from Ukraine and European Union environment regulations have blocked border crossings with Ukraine as well as motorways, and deliberately spilled Ukrainian produce from train wagons.

Previous incidents of grain being spilled from trains took place on the border with Ukraine last week.

Ukrainian President Volodymyr Zelenskiy said on Sunday it was important for Ukraine to maintain close relations with Poland, but that Kyiv was also ready to defend businesses that have been hurt by border blockades by Polish protesters.

"Unfortunately, the blockage continues," Ukrainian border service spokesman Andriy Demchenko said on television.

"In total, 2,200 lorries are queuing on Polish territory and (Polish) farmers are letting several vehicles through (in total) per hour in both directions. More blocked are those lorries coming from Ukraine," he said.

Ukraine has said the blockade caused serious economic losses and has hampered its war effort.

It says cross-border transportation has increased because of the war with Russia and the fact that its main export and imports routes through the Black Sea were blocked.

Farmers across Europe have been demonstrating over a range of grievances, including what they say is unfair competition from abroad, particularly Ukraine, after an EU decision in 2022 to waive duties on Ukrainian food imports in the face of the war with Russia. (Reporting by Pavel Polityuk Editing by Bernadette Baum and Angus MacSwan)