Talgat Musabayev said the Kazakh cosmonaut would fly to the "Russian segment" of the ISS, adding however, that "the financial components of the flight" had yet to be discussed at a meeting of a Russian-Kazakh commission.
He also expressed his gratitude to the Russian space agency Roscosmos.
Roscosmos earlier said a Russian space tourist hopeful would miss out on a trip to the stars in the autumn of 2009, with a Kazakh cosmonaut likely to take his place.
The Russian space agency had announced in 2007 that businessman and politician Vladimir Gruzdev would become the country's first Russian space tourist.
Gruzdev, a member of the ruling United Russia party, announced his plans to travel into space in April 2007. He later underwent a medical examination and was given the go-ahead to begin a space mission training program.
Boris Gryzlov, the speaker of the Russian parliament's lower house, earlier said United Russia could pay for Gruzdev's flight from party funds as a "contribution to the space program."