The league is meeting in Baghdad this week and is expected to issue a statement on Syria, a country it suspended in November over the violence that began a year ago and has claimed 9000 lives.
Syria's foreign ministry spokesman Jihad Makdisssi said yesterday: "Since its membership was suspended, Syria will only deal with Arab countries based on state-to-state relationships. Therefore we will not deal with any initiative issued by the Arab League at any level."
Syria blames the unrest on foreign-backed militants, who it says have killed around 3000 members of the security forces.
Relations between the Arab bloc and Damascus further soured after the league froze a monitoring mission in Syria and proposed a plan for Mr Assad to make a transition from power.
Arab leaders in Baghdad are expected to endorse a six-point proposal from UN-Arab League special envoy Kofi Annan, which seeks a ceasefire and political dialogue in what Iraq called a "last chance" for Syria.
Arab foreign ministers at the summit yesterday called for action on the plan. Mr Annan said on Tuesday that Mr Assad had agreed to the proposal, which does not demand the Syrian leader step down – a sticking point for the Syrian opposition, which insists any deal must require Mr Assad to leave power.
It stipulates Mr Assad must pull troops and heavy weapons from cities before peace talks with his opponents.
The move came as UN Secretary-General Ban Ki-moon urged Mr Assad to quickly implement the peace plan. Mr Ban said: "I strongly urge President Assad to put these commitments into immediate effect. There is not time to waste.
"This an important initial step that could bring an end to the violence and the bloodshed and provide aid to those people who are suffering."
Russia, meanwhile, called on Syria's opposition to accept the peace plan and urged foreign countries to press the foes of Mr Assad to comply.
Moscow, one of Mr Assad's main remaining allies, has repeatedly accused the Syrian opposition of blocking efforts to resolve the conflict.
Russia's foreign ministry said it was pleased to learn Mr Assad had accepted the peace plan.
"It is extremely important in this context for Syrian opposition groups to follow the example of Damascus and clearly declare their agreement with ... the peaceful resolution proposals of the UN-Arab League special envoy," it said in a statement.
"Obviously, much also depends now on external players, particularly those that are capable of influencing the opposition in a positive way."
Russia and China have shielded Mr Assad from UN Security Council condemnation by vetoing two Western-backed resolutions condemning his Government for the bloodshed.
Mr Annan's six-point plan does not specify that Mr Assad must step aside as a condition for a political dialogue in Syria. That pleases Russia, which accuses the US and its allies of using humanitarian concerns to push out governments they do not like. Moscow has said such a condition would be unjustified foreign interference in a sovereign state.