Describing the turnout as disappointing, Aljazeera's correspondent in Brasilia, Dima al-Khatib, said only Djibouti, the Comoros Islands, Algeria, Iraq, Qatar and Palestine were represented at the highest levels.
Only three more Arab prime ministers are expected to attend, but al-Khatib said organisers were pleased with Iraq's presence as it is the first international engagement for the country's new president.
Palestine's attendance is also deemed important coming at a time of significant political tension in the region.
Aljazeera learned that Brazil wants to be a member of a new peace plan quartet, which would work to help solve the Middle East conflict.
The current Quartet backing the road map peace plan consists of the United Nations, the European Union, the United States and Russia.
Summit officials said economic issues were most likely to dominate proceedings as the Gulf Cooperation Council (GCC) is expected to agree with the South American Mercosur group to create a free trade zone.
Mercosur includes Brazil, Argentina, Uruguay and Paraguay. Around 1000 businessmen from both sides of the Atlantic will also hold a forum on Tuesday morning.
Al-Khatib said Washington was annoyed with Latin America's strengthening ties with China, Russia and the Arab world and senior US officials said they were waiting to read about the summit's position on "terrorism" in particular.
Organisers in Brasilia have said the summit would not constitute a completing bloc to any government or international organisation.