JERUSALEM - Israeli soldiers headed to the polls on Sunday, two days ahead of a general election, the military said, as politicians made last-ditch appeals before nationwide voting gets underway on January 22.

The army said that the first military ballot boxes went into action at the defence ministry's massive Tel Aviv headquarters on Saturday for the benefit of "officers and soldiers unable to vote on Tuesday because of operational activity."

It said that voting would be extended to bases across the country on Sunday and Monday, in addition to Tuesday itself.

Outside the military, political infighting intensified as campaigning drew close to an end and parties scrambled to win the votes of the 15 percent of Israelis who weekend opinion polls said were still undecided.

The centrist HaTnuah of former foreign minister Tzipi Livni reportedly sought to disqualify one of the hardline pro-settler Jewish Home party's candidates after footage surfaced of him speculating about the destruction of Jerusalem's Dome of the Rock mosque, one of Islam's holiest sites.

Israeli television over the weekend screened a clip of US-born Jeremy Gimpel speaking to members of a Florida church during a 2011 trip to the United States.

"Imagine today if the dome, the golden dome -- I'm being recorded so I can't say blown up -- but let's say the dome was blown up, right, and we laid the cornerstone of the temple in Jerusalem, can you imagine?"

The chairman of the Central Elections Committee told army radio that he had yet to see a formal request to disqualify Gimpel, who is 14th on the Jewish Home's list.

With polls projecting the party to win between 12 to 15 seats in the new parliament, compared to three in the election of 2009, Gimpel's chances of winning a seat remain in the balance.

Jewish Home was also under fire from the nonagerian spiritual leader of the ultra-Orthodox Shas party, who lambasted the party's brand of Orthodox, rather than ultra-Orthodox, Judaism.

"They call it the Jewish Home, it's the gentile home," the firebrand Rabbi Ovadia Yosef said in comments broadcast Sunday on public radio. "Anyone who supports them is an unbeliever."

Yosef, 92, was discharged from hospital a week ago after suffering a mild stroke.

Elsewhere, the heads of the major parties were making final pitches in appearances across the country.

Livni was to appear at a rally in the town of Sderot, near the border with Gaza, while Labour leader Shelly Yachimovich was scheduled for a campaign appearance in Tel Aviv.

Israeli Prime Minister and Likud head Benjamin Netanyahu was expected at the funeral of a settler pioneer, in the settlement of Ariel in the northern West Bank, while Jewish Home head Naftali Bennett was stopping in at a military base.