Mr Netanyahu, Israel's prime minister, urged voters to back his conservative Likud Beiteinu bloc after casting his vote in Jerusalem's upmarket Rahavia neighbourhood, before visiting the Western Wall, Judaism's holiest site.
"Likud-Beiteinu represents all the people. The stronger Likud-Beiteinu is, the easier it will be to lead Israel successfully," he said.
His comments were aimed at reversing a surge in support for Naftali Bennett's Right-wing Jewish Home party, which advocates annexing large sections of West Bank land that the Palestinians want for a future state.
Officials said turnout was up on recent elections as unseasonably high temperatures and bright sunshine brought voters out in larger-than-expected numbers.