A Syrian opposition group has criticised the Arab League for giving a seat to the Syrian National Coalition, according to the Reuters news agency.
The lesser known Syrian National Co-ordination Body condemned the move at a news conference in Damascus on Monday.
Committee leader Raja al-Nasser said that the move would increase divisions within the Syrian opposition factions.
The Arab League allowed the SNC to take Syria's vacant seat last week at the organisation's annual summit in Doha.
Syria's membership to the Arab League was suspended in November 2011.
Yaser Tabbara, the spokesman for the Syrian National Coalition, has said that the group is taking serious measures to represent the Syrian opposition to the world.
"This is another excellent step in that direction, taking the seat in the Arab League, which will hopefully lead us into taking the seat in the United Nations and other regional and international organisations," Tabbara said.
But Nasser from the rival opposition group said the move is "an attempt to impose one of the sides on the Syrian people".
"This will have dangerous consequences for Syrian unity and will adversely affect the interests of the Syrian people," he said.
The SNC occupied the Arab League seat after Sheikh Hamad bin Khalifa Al Thani, the emir of Qatar, asked other Arab leaders to invite the opposition to formally represent Syria at the summit.
At the summit Moaz al-Khatib, head of the SNC, asked US secretary of state John Kerry for US forces to help defend rebel-controlled northern parts of Syria with Patriot surface-to-air missiles based in Turkey. NATO rejected the idea.
The summit endorsed the provision of military aid to Syrian rebels: A communique affirmed that member states had a right to offer assistance, "including military, to support the steadfastness of the Syrian people and the Free [Syrian] Army".