Jerusalem, March 17 (Xinhua) -- Israelis were casting their ballots Tuesday in a parliamentary election which is expected to be a close race for Prime Minister Benjamin Netanyahu's Likud party and its main rival, the center-left Zionist Union.

An estimated 45.4 percent of Israel's eligible voters cast their ballots at polling stations throughout Israel by 4pm Tuesday.

Up for grabs are the 120 seats in the Knesset and the reins of leadership of the entire country, with the party winning the most seats traditionally securing the first invitation from the president - currently former Likud stalwart Reuven Rivlin - to form a new coalition government.

Prime Minister Benjamin Netanyahu's Likud party has been trailing in the polls, between three to five seats behind the newly amalgamated Labor party, led by Isaac Herzog, and Hatnuah, headed by Tzipi Livni. The new joint list, Zionist Union, has maintained an almost consistent lead in the opinion polls since mid-February.

The Joint List, a coalition of four Arab parties, is running in third place.