Benjamin Netanyahu offered his "regrets" over remarks made on the day of the election that he said were not intended to offend Israeli-Arab citizens.
On 17 March, election day, the Israeli PM posted a Facebook message saying:"Right-wing rule is in danger. Arab voters are going to the polls in droves."
He added: "Left-wing organisations are bringing them in buses."
The Zionist Union, a centre-left alliance that represents Likud's main opposition, said Netanyahu's statement amounted to racism. "No other Western leader would dare utter such a racist remark," tweeted Zionist Union member Shelly Yachimovich.
"Imagine a warning that starts, 'Our rule is in danger, black voters are streaming in quantity to the polling stations.'"
Dr Yousef Jabareen, an attorney and expert in minority rights, spoke out at the first post-election meeting of the Higher Arab Monitoring Committee, condemning the Israeli PM for his statement.
"Could anyone imagine a European leader saying in a video clip that he was worried about high voter turnout among Jews in his country? Such a politician would not stay an hour in his job, and rightly so. However, in Israel it seems that anything goes and there is no limit to racist discourse," he said.
Netanyahu apologised for his comments, saying: "I know the things I said a few days ago hurt some Israeli citizens.
"My actions as prime minister, including massive investment in minority sectors, prove the exact opposite.
"I think, similarly, that no element outside the state of Israel should intervene in our democratic processes."
After his surprise win, Netanyahu says he hopes to form a new governing coalition in around three weeks, according to a BBC report.
Netanyahu and his Likud party gained the most number of seats with 30, while main rivals, the Zionist Union, scored 24 seats, out of a total of 120.