Sanremo, running Feb. 7-11, is a glitzy affair that attracts record audiences on TV and inspired the more famous Eurovision song festival. Zelenskiy is expected to briefly participate via video link on the closing night.
"I expect songs from the Italian song festival, not something else," Deputy Prime Minister and right-wing League leader Matteo Salvini said on the La7 TV channel on Thursday.
"If Zelenskiy has time ... to link up to the Sanremo festival, it's his choice," he continued, adding he was not sure "how appropriate" it was to mix entertainment with talk of war and death.
Zelenskiy, a former comedian and actor, also appeared via video message at this month's Hollywood Golden Globes awards. He used the platform to express confidence in victory in the war with Russia and thank "the free people of the free world" for their support.
Other Italian politicians, mostly from the far left and the formerly anti-establishment Five Star Movement, but also the opposition centre-left Democratic Party (PD), have echoed Salvini's misgivings.
"Zelenskiy at Sanremo? No," Gianni Cuperlo, a PD leadership candidate, wrote on Facebook, insisting that if RAI state TV wanted to broadcast a message from the Ukraine leader, it should not "confuse" it with the song festival.
Meanwhile, an online petition against Zelenksiy's invite, which partly blames the war on NATO and on Kyiv's "brutal repression" of Russian speakers, had attracted around 33,000 signatories as of Friday morning.
Italian Prime Minister Giorgia Meloni has been a firm supporter of Ukraine, and her government is close to finalising a deal with France on the supply to Kyiv of the SAMP/T air defence system.
But the issue has been a source of friction within her right-wing coalition, as it chafes with both Salvini's and conservative ex-premier Silvio Berlusconi's longstanding ties with Moscow.
Polls suggest that sending arms to Ukraine divides voters, with 52% of Italians opposing the decision against 39.9% in favour, in a Euromedia survey for RAI released on Wednesday.
The same poll showed that 38.2% of Italians want to end the war with a ceasefire deal with Russia, negotiated "behind the Ukrainians' back", and about 25% would cut arms shipments to Kyiv to pressure Zelenskiy into a surrender.
(Reporting by Alvise Armellini, editing by Gavin Jones and Frank Jack Daniel)
By Alvise Armellini