Other Arab leaders may follow suit, potentially spoiling a chance for Damascus to shore up its regional standing in the face of US pressure against it as a "rogue state".
"What we have heard is that if there is no president in Lebanon, King Abdullah and (Egyptian leader) Hosni Mubarak will not go," said a senior diplomat in Riyadh.
Saudi Foreign Minister Prince Saud Al Faisal said last month Syria should pressure its allies in Lebanon to reach a deal. He visited Russia and European capitals last week in what the diplomat said was an effort to solve the Lebanon impasse.
"Saudi Arabia wants to persuade Russia to tell the Syrians to stand back and allow a president to be elected," he said.
The election of a new Lebanese president has been delayed since November because of a dispute over the division of seats in the new cabinet between the Western-backed government and opposition backed by Syria and Iran.
A second diplomat said Saudi Arabia and Syria would continue to clash over Lebanon as Damascus sees it as key to its national security and Riyadh views it as part of its sphere of influence. "Those two visions are difficult to reconcile," he said.
Dubai-based analyst Mustafa Alani, who has close relations with the Saudi authorities, said Damascus was resigned to Saudi sending a low-level delegation to the late March summit but wanted to limit the fallout.
"They (the Saudis) will reduce their presence to the lowest representation possible as a means of protest. This will encourage others in the Gulf not to go, or to lower their representation. It will have an impact," he said. "The Syrians want to minimise damage. They want to secure the presence of other leaders to show the Saudis that they can act on their own."
