Deputy Foreign Minister Hossein Amir-Abdollahian said the plan, drafted after "detailed consultations" between Damascus and Tehran, was an amended version of an Iranian initiative presented last year.
The new proposals to be submitted to UN chief Ban Ki-moon amount to "one of the most effective and serious plans on the agenda of the United Nations and international players", Amir-Abdollahian told the Beirut-based Al-Mayedeen television channel that supports the Syrian regime.
But the channel said it was a four-point initiative calling for an immediate ceasefire, the formation of a national unity government, constitutional amendments on minority rights and elections to be held under international supervision.
Amir-Abdollahian said there had been "a strategic change in the attitude of the regional players with regards to Syria.
"If four years ago, many of the foreign players considered resorting to war as the solution for Syria, right now many of the players consider resorting to and focusing on a political solution as the most appropriate way to solve the Syrian crisis," he said.