Lukashenko recently called on Moscow and Kyiv to end the war, saying a military victory was unrealistic for either side. At the same time, he said Ukraine had nothing to fear from Belarus and apologised to Zelenskiy for harsh comments in the past.
"Lukashenko must demonstrate de-escalation beyond just words," Zelenskiy said in an interview with Ukrainian media. A mere apology from Moscow's closest ally was not enough, he said.
"He can keep his 'I apologise' to himself - that hasn't worked since the first day of the war."
Belarus is considered Russia's closest ally.
When Russian forces invaded Ukraine in February 2022, they also attacked in the direction of the Ukrainian capital Kyiv from Belarusian territory, but were forced to withdraw after suffering heavy losses.
Zelenskiy has been warning for weeks that Russia is trying to draw Belarus into the war and has cautioned Minsk against it.
In a lengthy post on X he accused Belarus of "helping Russian and Iranian drones strike Ukrainians with greater precision" and again dismissed Lukashenko's apology.
"Lukashenko received this information - and he must demonstrate de-escalation with more than just the words 'I'm sorry'. He can keep his "apology" to himself. It has meant nothing since the first day of the war," he said.
Kyiv says it is currently threatened by several Russian relay stations on Belarusian territory.
Ukraine says Russia is using these relay points to guide drones in attacks on targets in Ukraine.
Zelenskiy has repeatedly called on Lukashenko to dismantle the installations.
"If they don't switch it off, we will switch it off. Full stop."