The countries, who are officially at war, have no diplomatic relations.
Israeli athletes ignored the demands and boarded the bus anyway but the incident could not be resolved and the two teams subsequently had to travel to the ceremony in different buses.
al-Haj Nicolas told AFP news agency that he called for the door to be closed on the Israeli team, but they "insisted on getting on".
On Facebook, Udi Gal, a member of Israel's Olympic sailing team, echoed the words, saying his fellow competitors "insisted on boarding the bus".
Mr Gal said: “The bus driver opened the door, but this time the head of the Lebanese delegation blocked the aisle and entrance. The organizers wanted to avoid an international and physical incident and sent us away to a different bus.”
He added: "How could they let this happen on the eve of the Olympic Games? Isn't this the opposite of what the Olympics represents?"
“It is antisemitism pure and simple, and the worst kind of racism,” Ms Regev told Israel Radio. “The [International] Olympic Committee, which champions the separation of sports and politics, must condemn this vehemently and work to ensure that such behaviour is not repeated."
