On Facebook, Udi Gal, a member of Israel's sailing team, also said his fellow competitors had "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 organisers 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?"
As a result, event organisers tried to scatter the Israeli athletes on several different buses. Mr Gal called this "unacceptable for security and representative reasons".
Ms Regev told Israel Radio: "It is antisemitism pure and simple, and the worst kind of racism."
Meanwhile, Saudi Arabian judo competitor Joud Fahmy pulled out of her first-round match against Christianne Legentil from Mauritius in what the Hebrew media claimed was a move to avoid facing Israeli Gili Cohen in the next round.
According to the Saudi team, Ms Fahmy dropped out due to injury, but Channel 2 claimed that Ms Fahmy had not been hurt.
In another furore, some journalists at the Games reported that Israel had refused to let Palestinian swimmer Mary al-Atrash train in one of its Olympic-sized, 50m pools.
It later emerged that the Israeli government office for co-ordinating activities in the West Bank had offered Ms al-Atrash the use of a pool, but that she had not requested a permit for the trip.
Commentators also pointed out that while many Olympic athletes around the world train in 25m pools, there are several 50m pools in the Palestinian territories, including one in Gaza, one in Nablus and another in Beit Sakhour.
