Russia has said such a meeting would be pointless if it did not participate. Kyiv has previously proposed a world peace summit but has said Russia would not be invited.
Zelenskiy said in a television interview that he and the Swiss president would have to agree on the date between them and then send invitations to world leaders.
"We expect to have 80 to 100 countries." He added, "This is the number of countries, I believe, that will be able to at least try to force Russia to a fair peace."
In the interview, recorded during a visit to Chernihiv region, where he visited fortifications work on Friday, Zelenskiy said that they did not yet have a specific list of countries. "We will agree how it will happen in coming days," he said. "Days, I hope, not even weeks."
Asked about the role of Turkey, Zelenskiy said he was grateful to Turkish President Tayyip Erdogan for his support and desire to mediate, noting Turkey also had other interests and strong relations with Russia.
"Turkey as a mediator is not enough for us," he said. "Undoubtedly, they will be among those leaders, countries that can perform a mediation mission but not the mediation," he added.
Zelenskiy said the format of the summit would be very complex, bearing in mind the many interests involved in a summit involving so many countries, including historical and contemporary relations with Russia, Europe and elsewhere.
"Nevertheless, get all of them together, find the format, the way we go forward, and agree on it," he said.
(Reporting by Maria Starkova in Lviv, Ukraine, and Elaine Monaghan in Washington; Writing by Elaine Monaghan; Editing by Andrea Ricci)
