The NNA news agency said the bomber detonated his explosives-rigged vehicle yesterday at the checkpoint about 4.8 kilometers from the Syria border.
It wasn't immediately clear if the casualties were bystanders or Hezbollah fighters.
It was the first such bombing since February. The attack was likely linked to the war in neighbouring Syria.
Sunni militants, including the Islamic State group, are trying to punish the Iranian-backed Hezbollah because its fighters are battling alongside forces loyal to Syrian President Bashar Assad.
Sunni militants claimed responsibility for previous bombings in Lebanon.