Polish farmers will step up protests on the border with Ukraine on Tuesday, blocking almost all traffic in what they say is a bid to save their livlihoods but which Kyiv says is damaging its war effort.

Farmers across Europe have been demonstrating against constraints placed on them by European Union measures to tackle climate change, as well as rising costs and what they say is unfair competition from abroad, particularly Ukraine.

"(There will be a) total blockade of all traffic at border crossings," said Adrian Wawrzyniak, a spokesperson for the Solidarity farmers' union.

Wawrzyniak said that while military aid would be allowed through, passenger traffic would be blocked, not only lorries. He said there would be blockades at ports and of motorways.

Kyiv says that its agricultural exports through eastern Europe have not damaged EU markets. As exasperation with a series of protests by farmers and truckers in Poland has grown, Ukrainian hauliers said they planned a peaceful round-the-clock protest at three crossings already blocked by Polish farmers.

In a comment to the Ukrinform news agency, their representative said they would control movement at crossings preventing Polish trucks from bypassing the general queue. The protest is planned to last till March 15.

Ukraine says the blockades are affecting its defence capability and helping Russia's aims.

Ukrainian President Volodymyr Zelenskiy said on Monday the situation at the border demonstrated "the erosion of solidarity on a daily basis".

He added that only 5% of Ukraine's agricultural exports passed through the border with Poland, adding that the case was more about politics than about grain.

"We need common decisions, rational decisions, to resolve this situation. The decisions made by us and the Poles, first of all, and by everyone in Europe who cares about the fate of Europe," he added.

(Reporting by Anna Wlodarczak-Semczuk, Alan Charlish, Pawel Florkiewicz in Warsaw, Yuliia Dysa in Gdansk Editing by Gareth Jones)