JERUSALEM, March 17 -- Israelis went to the polls on Tuesday in a parliamentary election where the opposition center-left Zionist Union is posing a strong challenge to the ruling Likud party led by Prime Minister Benjamin Netanyahu.

A total of 24 parties are vying for 120 seats in the parliament. According to opinion polls, only 11 can get more than 3.25 percent of the votes, as required by the election law, to make it into the parliament.

Here is a look at some of the main Israeli political parties.

LIKUD PARTY

The right wing Likud party has been in power since 2009. It campaigns on security issues, with Netanyahu maintaining hardline stances on Iran's nuclear program as well as the Palestinians.

The party has been criticized for lacking an agenda on socio-economic issues such as high living costs and housing crisis.

In the 2013 elections, Likud joined forces with Foreign Minister Avigdor Lieberman's Israel Beytenu party and the two received 31 seats together (20 for the Likud), with a significant lead over their nearest contender, the Yesh Atid party, which got 19 seats. Israel Beytenu broke its union with the Likud in July 2014.

ZIONIST UNION

The Zionist Union is a joint list combining the historic left-wing Labor party, headed by parliament member Isaac Herzog, and centrist Hatnua (The Movement), a two-year old party led by former Justice Minister Tzipi Livni.

The alliance was formed in December 2014, aiming to be an alternative to the Likud's rule.

Herzog has pledged to stop the Jewish construction outside major settlement blocs in the Palestinian territory, and to "reignite" the negotiations with the Palestinians.

He also emphasized his economic platform, which promises to restrain the high cost of living in the country, particularly the housing prices.

Latest polls showed that the Zionist Union is maintaining a four seat advantage over Likud.

JEWISH HOME

Jewish Home, a nationalistic right-wing party headed by Economy Minister Naftali Bennett,is a substantial force in Israeli politics.

It is expected to gain more than the 12 seats it garnered in the 2013 elections. It supports construction in the Jewish settlements and the annexation of West Bank territories.

YESH ATID

Yesh Atid, a center-oriented party led by former journalist Yair Lapid, had been a dark horse in the 2013 elections, gaining 19 seats in the parliament.

It had been a vital partner of Netanyahu's ruling coalition, with Lapid serving as finance minister in the cabinet.

Lapid was fired by Netanyahu for an alleged joint attempt with Livni to topple his government.

Lapid's popularity dipped due to the controversial tax hikes policy he pursued, the slowest growth rate in the past four years, the high costs of living and the housing crisis.

Current polls put Lapid and his party at 12 seats, but some political pundits believe the party will receive more votes on the elections day.

KULANU

Kulanu is a new centrist party formed by Moshe Kahlon, a former Likud member and one of the most popular Israeli politicians in recent years.

While serving as communication and welfare minister in Netanyahu's previous cabinet, Kahlon opened the cellphone providers market for competition and substantially decreased the amounts Israelis pay for their mobile phone calls.

The party's agenda is mainly focused on socioeconomic issues, and polls predict it would get between seven and ten seats in the Knesset.

THE JOINT LIST

The Joint List is composed of three Arab parties and Hadash, a joint Jewish and Arab communist party.

The joint list, announced in January and headed by recently appointed Hadash leader Ayman Odeh, was established in response to the controversial governance law, which raised the electoral threshold from 2 to 3.25 percent of the votes, threatening the existence of the parties individually.

Some believe the law was intentionally designed to hurt the Arab parties, which far-right wing politicians deem a fifth column in Israeli politics.

The alliance is predicted to garner 13 seats in the Knesset, becoming a major parliamentary faction. The list advocates for co-existence and equal representation for Israeli Arabs, who constitute 20 percent of the population, and improvement of the ties between Jews and Arabs.

ISRAEL BEYTENU

Israel Beytenu, an ultra right-wing party led by Lieberman, is predicted to take a significant crash in the upcoming elections, mainly due to an unfolding corruption scandal in which several senior party members are involved.

The party, which got 11 seats in the 2013 elections, is predicted to get only six seats in the new Knesset.

Lieberman has been known for his far-right stances on Israeli Arabs and Palestinians. He has offered to transfer the Israeli Arab population to a future Palestinian state and called for re-conquering the Hamas-held Gaza Strip.

SHAS AND UNITED RORAH JUDAISM PARTY

Shas is formed mainly by ultra-orthodox Sephardic Jews from Arab states, and the United Torah Judaism Party by the ultra-orthodox Ashkenazi Jews from Europe. Both are major religious parties in Israel and are expected to win seven seats respectively.

MERETZ

A historic left wing party, headed by Zehava Gal-on, advocates peace with the Palestinians and economic equality. It is expected to get between five to six seats.

YACHAD

The Yachad party may cross the threshold and receive four to five seats in the Knesset.

This far-right wing party was recently established by former Shas leader Eli Yishai and Baruch Marzel, a far right-wing activist who headed the racist Kach movement, which was outlawed in 1994.