In an interview posted on the Foreign Ministry website on Thursday, Lavrov stressed the key role that Iran is playing in regional developments, but added that some Western states wanted to limit the participants and possibly predetermine the outcome of the talks.
"Among some of our Western colleagues, there is a desire to narrow the circle of external participants and begin the process from a very small group of countries in a framework which, in essence, would predetermine the negotiating teams, agenda, and maybe even the outcome of talks," Lavrov said.
Iran has already welcomed the proposal and announced its readiness to participate in a June 2012 meeting on Syria hosted by the United Nations in Geneva.
"One must not exclude a country like Iran from this process because of geopolitical preferences. It is a very important external player," Lavrov said in the interview given to a Lebanese television station.
Last year the foreign ministers of the U.N. Security Council's five permanent members - Russia, the United States, China, France and Britain - all attended the Geneva talks along with Turkey, Kuwait, Qatar, U.N. Secretary-General Ban Ki-moon, Arab League head Nabil Elaraby and EU foreign policy chief Catherine Ashton.
Lavrov also said Saudi Arabia, a foe of Damascus and leading backer of the terrorist groups which did not participate in last year's meeting, should be present.
He said he would not exclude any political opposition groups, but that "terrorist groups" like the al Qaeda-linked Nusra Front had no place at the negotiating table.