Israel's governing Likud Party approved teaming up with an ultranationalist partner on Monday, forming a hawkish bloc that appears poised to win parliamentary elections in January.

The move to join Prime Minister Benjamin Netanyahu's Likud Party with Yisrael Beitenu, which is headed by Foreign Minister Avigdor Lieberman, passed by a large majority Monday evening at a meeting of Likud activists.

"I came here today to ask you to vote for a strong Likud, a strong prime minister, a strong government and a strong Israel," Netanyahu said.

Netanyahu said that during his term Israel has mostly weathered the global economic crisis and has strengthened its security. But he warned that economic and security challenges remain.

"I believe that at this time it is crucial that the national camp join forces, and that is the reason why I asked Avigdor Lieberman to run on a joint list with us with the Likud," he said.

Lieberman later issued a statement welcoming the vote calling it an "important and historic step that will strengthen Israel."

The move, announced last week, has been criticized by some members of the Likud, who worried that the partnership would wrench their party sharply toward the secular right, but Netanyahu was greeted with loud applause as he addressed the gathering.

Polls have shown the combined Likud and Yisrael Beitenu list, along with religious parties that traditionally align with Likud, could control a majority in the 120-member parliament, but they have shown no boost beyond the current strength of the separate parties.

The tie-up has raised speculation that centrist parties may also band together as a bloc in response.

Avraham Diskin, a Hebrew University political scientist, said the move could backfire on Netanyahu by making him appear more as a hard-liner and alienating some of the Likud's traditional and religious supporters.

"It will definitely be perceived at least as being more right wing than it traditionally has been. Netanyahu this term did his best to be more centrist than hawkish," he said.

During his term, Netanyahu became the first Likud leader to support the idea of a Palestinian state, though with conditions rejected by the Palestinians. He also approved a short-lived freeze on West Bank settlement construction in a failed attempt to revive peace talks.

Diskin said religious Jewish voters of Middle Eastern background might turn to other alternatives because of Yisrael Beitenu's reputation as a party dominated by fiercely secular immigrants from the former Soviet Union. Lieberman, himself an immigrant from Moldova, has fought to bring civil marriage to Israel, an idea opposed by the religious establishment.

"This union deters voters across the board," he said. Religious voters could turn to smaller, religious parties, while Likud centrists might leave to more moderate parties because of Lieberman's dominant position.

In his speech, Netanyahu promised that Likud would not change its platform and would remain true to its ideals of "preserving the state's security, preserving the Land of Israel."

Since Netanyahu announced last week that he wanted to join forces with Yisrael Beitenu, there has been speculation that dovish parties might form their own bloc in response.

A poll released before the Likud approval showed a joint Likud-Israel Beiteinu list could finish far ahead of dovish rivals in Jan. 22 elections.

The TNS/Teleseker poll of 500 people, conducted for the Maariv newspaper, gave the merged party 43 of parliament's 120 seats. Ultra-Orthodox parties that traditionally align with Likud would win 24, potentially handing Netanyahu a comfortable hard-line majority of 67 seats.

The survey had a margin of error of 4.5 percentage points.