The movement, which was behind an armed uprising in the 1980s that marked the biggest challenge to the Damascus government to date, called for a national congress of all political parties to ward off what it said was a "threat of invasion", an allusion to growing US pressure on the government.
"The Muslim Brotherhood urges the organisation of an inclusive national congress that would represent all political tendencies and religious and ethnic groups, whether based inside Syria or in exile, to form a national force capable of facing the challenges," the Muslim Brotherhood said in a statement on Monday.
"The Muslim Brotherhood calls for an end to the state of emergency (in force since the Baath party seized power in 1963) and the winding up of the courts of exception, which have been the instruments of injustice."
The banned party called for the "adoption of a law on political parties and the organisation of free and fair elections for a national assembly that would draw up a new constitution to deal with the needs of the moment and usher in a democratic republic".
The Islamist group warned of the "huge earthquake ... on our borders which threatens to invade", a reference to the US-led force that overthrew the Baath party government in neighbouring Iraq in April 2003.
The US has stepped up pressure
for democracy in Syria
"The Baath party, which has led the country for 42 years, bears the sole responsibility for the destruction it will cause if it insists on continuing its policies and ignoring honest appeals."
The group said it was acting "not out of fear that the regime might fall but out of concern for the losses to the country if it slides into anarchy".
Washington has stepped up pressure for democracy in Syria in recent weeks, receiving a small US-based opposition group at the State Department and calling for democratic reforms through US-funded Arabic language media.
"The president has made clear that our foreign policy is very much focused on what we can do to help people have more opportunity, have more of a voice," Deputy Assistant Secretary of State Liz Cheney said on Thursday.
"We talk to many different groups to get their input and their thoughts about what the United States should be doing, or could be doing, about what's happening on the ground in Syria"
Deputy Assistant Secretary of State
"And so we talk to many different groups to get their input and their thoughts about what the United States should be doing, or could be doing, about what's happening on the ground in Syria, about the Syrian people's hope for freedom and democracy."
Daughter of Vice-President Dick Cheney, Liz Cheney is the coordinator for Broader Middle East and North Africa Initiatives, Washington's campaign for democratisation in the region.