Israel's Prime Minister Benjamin Netanyahu has won a re-election in what would be his fifth term as head of a coalition government.

With more than 99 per cent of votes counted, Netanyahu's conservative Likud Party has won following his challenger conceding defeat.

Netanyahu is poised to become the longest-serving Israeli prime minister in July, overtaking the country's founding father, David Ben-Gurion.

However, he faces possible indictment in three graft cases, following corruption allegations that could mean his removal from government.