United Nations chief Ban Ki-moon is expected to attend the opening in Riyadh of the Fourth Summit of South American-Arab Countries, set to begin at 1600 GMT.
State television showed the arrival of President Nicolas Maduro of Venezuela, whose country belongs to the Organisation of Petroleum Exporting Countries along with Saudi Arabia, the world's biggest oil exporter.
President Rafael Correa of Ecuador, OPEC's smallest member, also arrived. It was not immediately clear whether other Latin American heads of state would be present.
Other leaders include Gulf rulers and King Abdullah II of Jordan.
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Ahead of the two-day meeting, Sudanese Foreign Minister Ibrahim Ghandour said windows of cooperation have long existed "but haven't been open enough to take advantage of the capabilities" of both regions.
For example, Sudan has land and water "that could enable it to become the Arab and South American food basket".
The summit between the 22 Arab League members and 12 nations from South America was first held in 2005.
Ahead of the summit, Arab League Secretary General Nabil al-Arabi told Kuwait's KUNA news agency that "trade between both regions has amounted to USD 30 billion after it was no more than USD 6 billion in 2005."
Peru, which hosted the third meeting in 2012, last month became one of 12 Pacific rim countries to seal the world's largest free trade area, known as the Trans-Pacific Partnership.
Chile is the only other South American nation included in that deal.
Saudi columnist Abdulateef al-Mulhim yesterday in Arab News, said that together, the Arab and South American regions can help bring prosperity and stability to the world.
Saudi Foreign Minister Adel al-Jubeir spoke of a "convergence of positions" between countries of the two regions on many issues and commended the Latin American nations' "positive stance" towards the Palestinian question.