JERUSALEM—A pair of polls show that the Israeli premier's new alliance with his hard-line foreign minister has failed to produce a boost but could keep them in power after the Jan. 22 election.

Israeli Channel 2 TV's poll Sunday showed the new bloc of Benjamin Netanyahu's Likud and Avigdor Lieberman's Yisrael Beiteinu would maintain the 42 seats they currently hold in the 120-seat parliament. Netanyahu had hoped the merger would boost their numbers.

The poll surveyed 500 people and had a margin of error of four percentage points. It said the Labor Party would finish second with 23 seats.

A separate poll on Channel 10 showed the new hard-line bloc dropping seven seats from its current total. The TV channel did not provide details of how the poll was conducted.