Louay Safi, spokesman of the opposition group, announced here that it was suspending its participation unless the UN cancelled its invitation to Iran or Iran accepted the Geneva I communique, Xinhua reported.
The Istanbul-based coalition, which earlier decided to participate, threatened to pull out of the conference shortly after Iran was invited to participate in the meeting.
Meanwhile, Alaeddin Boroujerdi, chairman of the National Security and Foreign Policy Committee of Iran's Majlis, said Tehran would participate in the upcoming conference on the Syria crisis without accepting the 2012 Geneva communiqué, reported Press TV.
The invitation for Iran to take part in the conference showed they have realised the fact that the conference would be a non-starter without Iran's presence, said Boroujerdi.
"Given the official invitation and while insisting that it won't accept any preconditions, Iran is expected to attend the talks... at a high-level to help the Syrian government and nation get rid of the crisis imposed on the country," he said.
Boroujerdi said the invitation extended by UN Secretary General Ban Ki-moon to Iran for participation in the talks has been fully approved by all the five permanent members of the Security Council, including the US.
Commenting on the statement by the the SNC, Boroujerdi said there have been serious divisions among Syrian opposition groups ever since the Syrian conflict broke out, and foreign-sponsored militant groups operating inside Syria apparently cannot play a determining role in ending the conflict gripping the Arab country.
Geneva II is an international conference to find a political solution to the conflict in Syria and is set to begin in the city of Montreux in Switzerland Jan 22. For months, UN, US and Russian diplomats have struggled to persuade both the Syrian regime and rebels opposed to it to attend the conference.Ban Sunday said that he had invited Iran to attend this week's Syria peace conference.
"I have decided to issue some additional invitations to the one-day gathering in Montreux. They are Australia, Bahrain, Belgium, Greece, the Holy See, Luxembourg, Mexico, the Netherlands, the Republic of Korea and Iran," Ban said.
Ban and Iran's Foreign Minister Mohammad Javad Zarif have discussed the Syrian crisis and agreed upon the implementation of the June 30, 2012 communiqué, including the action plan, the UN chief said.
The Geneva communiqué calls for a transitional government in Syria without any role envisaged for President Bashar Al-Assad in the country's future.
Meanwhile, the US said the UN invitation to Iran to participate in the conference should be rescinded unless Tehran "fully and publicly" accepted the Geneva I communique.