The document is ready and will be presented to the UN Special Envoy for Syria Staffan de Mistura next week, Lavrov said, speaking at a news conference in Baku, Azerbaijan, after the ministerial meeting of the Black Sea Economic Council (BSEC), Anadolu Agency reported.
Lavrov said he discussed the issue with his Turkish counterpart Mevlut Cavusoglu on the sidelines of Friday's BSEC talks and with his Iranian counterpart Mohammad Javad Zarif over the phone on Thursday.
Last month, Syria’s warring sides and mediators failed to agree on the formation of the committee, which is seen as key to ending Syria’s seven-year-old war.
During the Syrian peace conference in late January in Sochi, the formation of the committee to amend the Syrian Constitution was agreed upon.
Syria has been locked in a conflict since early 2011.
Since then, hundreds of thousands of people have been killed and more than 10 million others displaced, according to UN officials.