By Patrick Graham

WARSAW, Nov 17 (Reuters) Poland stuck to its guns today in a trade row with Russia, repeating that it would use its veto to block a landmark EU-Russia strategic partnership if a ban on its food products was not lifted by Moscow.

Warsaw is blocking consensus in the 25-nation EU on a negotiating mandate for a new agreement due to be initiated at an EU-Russia summit in Helsinki on November 24, in protest over a Russian ban on imports of meat and some other foods from Poland.

European Union president, Finnish Prime Minister Matti Vanhanen, was due to visit Warsaw later today for talks with his Polish counterpart, Jaroslaw Kaczynski, in an attempt to break the deadlock.

Polish Agriculture Minister Andrzej Lepper told a news conference only the reopening of Russian markets to Polish produce would persuade Warsaw to back down.

''Our farmers lost a very large amount due to this (ban),'' Lepper said. ''Our minimum scenario is the opening of the Russian market which was closed almost exactly a year ago.'' Russia banned imports of Poish meat and other foods last year after finding some veterinary certificates had been forged.

The European Commission is trying to help by sending a fact-finding mission of experts to verify that Polish food exports meet EU health and safety standards in a bid to persuade Moscow to lift the ban.

Farm Ministry officials said the mission was part of a regular inspection that had already given Poland an all-clear in July, and that they expected the team to back the Poles' case.

Warsaw says the import ban is politically motivated and aimed at splitting the EU and discriminating against former Soviet satellite countries that stand up to Moscow.

Russia has said the Polish stance is tantamount to unacceptable blackmail, but the Poles have gained declarations of support from Lithuania and France this week and believe they are gaining ground.

''There is already understanding that we are in a difficult position, that we are not being extreme,'' Andrzej Krawczyk, Polish President's Lech Kaczynski's foreign policy adviser, told private radio TOK FM.

And he hinted there might be some room for compromise beyond the official hard line: ''We have shown we can be tough ... it is important now to show we can be reasonable.'' REUTERS PDM HT1755