"I don't believe that Prime Minister Netanyahu would do that. I think he would be ill-advised to do that," Biden said in an interview with CNN, when asked about possible Israeli strikes on Iranian nuclear sites.
"My level of concern is no different than it was a year ago," he added.
Presenting his new government to Israel's parliament a week ago, Netanyahu alluded to an eventual nuclear-armed Iran as the biggest threat to his Jewish state.
"The biggest danger to humanity and to Israel comes from the possibility of a radical regime armed with nuclear weapons," Netanyahu said, making clear his remarks were aimed at Iran.
President Barack Obama's administration has repeatedly said that all options are on the table for dealing with Iran, but is trying to launch a new dialogue with the Islamic republic after a three-decade freeze in relations.