The Spice Girl was reportedly due to perform in the city of Zakopane on Saturday.
In a statement posted on Monday, she wrote: “In light of some issues that have been brought to my attention, that do not align with the communities I support, I’m afraid I will no longer be able to perform in Poland as planned on New Year’s Eve.
“I hope to be back there very soon. Hope you’re all having a wonderful Christmas and best wishes for 2023. Melanie xxx.”
While Melanie did not elaborate further on her reasons for pulling out of the gig, she is an ally of the LGBTQ+ community, winning the celebrity ally award at last year’s British LGBT Awards.
In Poland, LGBTQ+ people face opposition from the country’s conservative government and some local communities.
President Andrzej Duda and some MPs from the ruling party have claimed the movement for civil rights for LGBTQ+ people is a threat to traditional families.
Dozens of towns in conservative parts of eastern and southern Poland have declared themselves to be free from “LGBT ideology”, known often as “LGBT-free zones”.