Polish Prime Minister Mateusz Morawiecki has said Poland will not allow itself to be "flooded with Ukrainian grain" regardless of Brussels' decision on Ukrainian agricultural products imports.

The EU embargo on the import of wheat, corn, sunflower seeds and rapeseed to five countries neighbouring Ukraine expires on Friday. Poland is seeking to extend this ban, and if this does not happen, Poland is threatening to introduce a unilateral embargo.

"Poland will not allow itself to be flooded with Ukrainian grain. Regardless of the decision by Brussels officials, we will not open our borders," Morawiecki said on Facebook, posting a pre-election video for the ruling Law and Justice party.

Morawiecki in his pre-election video said, "When we needed to help our neighbours, we opened our hearts and homes. That's the Polish people’s nature".

But he added, "when we have to fight for Polish interests, only a Law and Justice government guarantees that the interests of our farmers will be protected."

"We say no to disrupting the Polish agricultural market and harming consumers and manufacturers. It was our tough stance that stopped Ukrainian grain imports from entering the EU common market," Morawiecki said.

The Polish government is preparing a draft decision to extend the ban on importing Ukrainian agricultural products after 15 September.

Ukraine insists that a unilateral extension of the ban would violate the rules of the common market and the EU-Ukraine Association Agreement.