The Kyiv government wants the German-made Leopard 2 tank to break through Russian lines and recapture territory this year.
Pressure on Berlin - which must approve re-exports of the Leopard - also came from EU foreign ministers meeting in Brussels. Latvia's foreign minister said "there are no good arguments" why the battle tanks could not be provided.
The issue has dominated recent discussions among Western allies about how much and what sort of material aid they should give Ukraine as the first anniversary of the Russian invasion nears.
Polish Prime Minister Mateusz Morawiecki, whose country neighbours Ukraine, said on Monday Warsaw would ask Germany for permission to re-export tanks to Ukraine.
But he added: "Even if we did not get this approval... we would still transfer our tanks together with others to Ukraine. The condition for us at the moment is to build at least a small coalition of countries."
Germany's foreign minister appeared to hold the door open to approval of such shipments on Sunday when she said Berlin would not stand in the way if Poland wanted to send them.
Ukraine and Russia are both believed to be planning spring offensives to break deadlock in what has become a war of attrition in eastern and southern Ukraine. Current fighting is centred on the town of Bakhmut in the east, where Russia's Wagner mercenaries and Ukrainian forces have been locked in battle.
Ukrainian President Volodymyr Zelenskiy meanwhile was grappling with a corruption scandal which could dampen Western enthusiasm for his government.
A newspaper reported that the Ukrainian military had allegedly secured food at highly inflated prices, and a deputy minister resigned after an investigation into allegations he accepted a bribe.
LEOPARDS ON THE MOVE?
Ukrainian officials have been pleading with Western allies to supply them with Leopard tanks for months. Germany has so far held back from sending them and says other NATO countries have yet to formally ask to re-export them.
After Ukrainian advances in the second half of 2022, frontlines have been largely frozen in place for two months, despite heavy losses on both sides. Ukraine says Western tanks would give its ground troops the mobility, protection and firepower to break through Russian defensive lines and resume their advance.
"We need tanks - not 10-20, but several hundred," Zelenskiy's chief of staff Andriy Yermak wrote on Monday on Telegram. "Our goal is (restoring) the borders of 1991 and punishing the enemy, who will pay for their crimes."
Western allies pledged billions of dollars in weapons for Ukraine last week but failed to persuade Germany to commit to allowing Leopards.
In an apparent shift in Germany's position, foreign minister Annalena Baerbock said on Sunday her government would not block Poland if it tries to send its Leopards. Arriving in Brussels on Monday, Baerbock declined to elaborate on those comments or say if she had been speaking for the whole government. She said it was important to "do everything we can to defend Ukraine".
Chancellor Olaf Scholz's Social Democrat party argues the West should avoid sudden moves that might escalate the war. But a number of allies reject that position, saying Russia is already fully committed to its assault on Ukraine.
"At this point there are no good arguments why battle tanks cannot be provided," Latvian Foreign Minister Edgars Rinkevics said. "The argument of escalation does not work, because Russia continues escalating."
Lithuanian Foreign Minister Gabrielius Landsbergis said the tanks should not be held up one more day, while Luxembourg's Foreign Minister Jean Asselborn said Russia could win the war if Europeans "don't help Ukraine with what they need now".
'TERRIBLE WAR'
American lawmakers pushed their government on Sunday to export M1 Abrams battle tanks to Ukraine, saying even a symbolic number would help push European allies to do the same.
Britain has said it will supply 14 Challenger 2 tanks to Ukraine. French President Emmanuel Macron said he did not rule out the possibility of sending Ukraine Leclerc tanks.
Leopards are seen as the best option for Ukraine because they are more widely available than the British and French tanks, and use less fuel than the turbine-powered U.S. Abrams.
The Kremlin said on Monday the splits in Europe over whether to provide tanks to Kyiv showed there was increasing "nervousness" within the NATO military alliance.
"But of course all countries which take part, directly or indirectly, in pumping weapons into Ukraine and in raising its technological level bear responsibility" for continuing the conflict, Kremlin spokesman Dmitry Peskov said.
The EU foreign ministers meeting were also due to discuss more military aid for Ukraine. EU foreign policy chief Josep Borrell said he hoped they would approve another 500 million euro ($545 million) tranche of support.
Since its invasion on Feb. 24, 2022, which it has cast as defending itself from an aggressive West, Russia has taken control of parts of Ukraine it says it will never return. Ukraine has said that restoring its territorial integrity is not open for negotiation.
(Reporting by Pawel Florkiewicz, Anna Wlodarczak, Tom Sims and Lidia Kelly, Writing by Angus MacSwan, Editing by Clarence Fernandez)
