Other EU border countries have also warned that thousands of refugees could flee to their country in the event of a Russian attack.
Poland's government is making preparations ahead of a possible influx of refugees from neighbouring Ukraine.
Interior minister Mariusz Kaminski said on Sunday that his country was prepared for "various scenarios" but hopes that a worst-case scenario can be averted.
Poland is the largest European Union member state to border Ukraine and has so far maintained its diplomatic missions in Kyiv.
Warsaw says its staff may be needed to facilitate a large-scale exit of Ukrainians in the event of another Russian attack.
Poland has welcomed large numbers of Ukrainian economic migrants in recent years, particularly after Russia’s incursions into Ukraine in 2014.
The EU country has now been making plans to accept refugees if it comes to that, added deputy foreign minister Marcin Przydacz.
“In this worst-case scenario, we are not talking about hundreds or thousands, but much larger numbers,” he told Radio Plus on Monday.
He added that the interior ministry has been preparing “internal scenarios, infrastructure and plans” for many weeks.
The plans would include housing refugees in hostels, dormitories, sports facilities and other venues.
Polish officials, including town mayors, have been asked to draw up reports of what facilities they could make available.
Ukraine is also bordered by EU member states Hungary, Romania, and Slovakia, as well as a non-EU state Moldova.
Hungarian prime minister, Viktor Orban, has warned that a Russian invasion of Ukraine could send hundreds of thousands of Ukrainian refugees fleeing across the border.
Slovakia's government says it is also preparing for a wave of refugees in the case of a conflict.
“According to the existing studies and analysis, I can say that even a limited Russian military attack on Ukrainian territory would mean tens of thousands of refugees crossing our border,” Slovakian defence minister Jaroslav Nad said.
“From the European continent’s perspective, the current situation is the most dangerous since World War II,” he added.