Israeli President Reuven Rivlin, a member of the conservative Likud party, is under fire from right-wing Israelis after he denied the pardon request on Sunday of a former Israeli soldier who shot dead a wounded Palestinian attacker.

Elor Azaria was an army medic in March 2016 when he was videotaped by human rights organization Betselem shooting Fatah al-Sharif, who was already incapacitated after attempting to stab Israeli soldiers.

Azaria, 21, was found guilty of manslaughter in January for the incident. He was sentenced to 18 months in prison and had his sentenced reduced by four months by the Israeli army chief Gadi Eizenkot.

On Monday, police opened an investigation following a slew of photo-shopped images of Rivlin wearing an Arabic head covering known as a kaffiyeh.

Posting photos of Israeli leaders in a kaffiyeh, which doubles as a symbol for Palestinian nationalism, is taboo in Israeli society since similar pictures of Prime Minister Yitzhak Rabin were circulated by right-wing Israelis before Rabin's assassination by a Jewish extremist in 1995.

Rivlin's pardon denial puts an end to a case that has split Israel, with many stating that Azaria is a hero. Israeli Prime Minister Benjamin Netanyahu and other leading politicians have called for the soldier to be pardoned.

Culture Minister Miri Regev attacked Rivlin on Sunday saying he "abandoned" Azaria. "It's very unfortunate that President Rivlin gave in to improper pressure and chose to abandon Elor," she said.

Defence Minister Avigdor Lieberman called Azaria a "outstanding soldier."