Voting is under way as Israel's ruling Kadima party chooses a successor to its leader, Prime Minister Ehud Olmert.
Members of Israel's ruling Kadima party have elected Foreign Minister Tzipi Livni as their new leader by a large margin, exit polls suggest.
The front-runners to succeed him are Foreign Minister Tzipi Livni and Transport Minister Shaul Mofaz.
Ms Livni beat Transport Minister Shaul Mofaz by a margin of 48% to 37%, according to two television exit polls.
Mr Olmert, who denies corruption claims, has said he will step down as PM after his successor is chosen.
Voting in the election officially closes at 1930 GMT.
With turnout among the party's members at less than 40% just hours before polls closed, voting has been extended by half an hour.
Prime Minister Ehud Olmert, who denies corruption claims, has said he will step down from the post after his successor is chosen.
Mr Olmert may stay on as caretaker prime minister until a new coalition government is formed, which could take weeks or even months.
Ms Livni's supporters hope she will breathe new life into a political establishment mired in sleaze and dominated by ageing, male, former military figures, says the BBC's Heather Sharp in Jerusalem.
But the former Mossad spy is widely criticised for her lack of political experience.
Mr Mofaz, a former army chief of staff who has talked tough on Iran, is seen as further to the right on security, but some say there is little difference between him and the opposition Likud party, our correspondent adds.
Despite the low turnout, correspondents say voting tends to pick up in the evening as Israelis return from work.
Security key
Some 70,000 members of Kadima, which describes itself as centrist, are eligible to vote.
Early results are expected soon after polls close at 2230 local time (1930 GMT). The winner must get more than 40% of the vote to avoid a run-off a week later.
Ms Livni has consistently led in polls, but Mr Mofaz is thought to have a stronger base of influential activists, our correspondent says.
Morning voting was steady at the party's main office in Jerusalem, which was decked out with flags and posters for both Mr Mofaz and Ms Livni, our correspondent reports.
"I think [Ms Livni] very intelligent and she has a good proposition on peace," one voter Dana Shapiro told the BBC.
Another voter, Yitzak, said: "Mofaz is a security man, and this is what we need right now."
Casting her vote in Tel Aviv, Ms Livni urged voters to turn out: "You can determine today what the character of Kadima will be... You can determine today if you really have had enough of old-time politics."
Mr Mofaz said he was confident of victory as he voted in Kfar Saba.
Earlier, he told Israeli army radio the country "stands before major challenges in the coming years and needs a strong leader who has the courage to decide and the ability to act".
Popularity waning
Kadima was formed three years ago when former Prime Minister Ariel Sharon split from Likud to draw together support from left and right for his policy of unilateral withdrawals from the Gaza Strip and parts of the West Bank.
But its poll ratings have fallen as a stroke left Mr Sharon in a coma, while his successor, Mr Olmert, faced strong criticism of his handling of the 2006 Israel-Lebanon war and was investigated in several corruption scandals.
Polls now suggest Likud could win a potential general election, which would take place if a coalition government cannot be formed in the wake of the Kadima leadership vote.
The Kadima election comes as the US government is continuing its push for an Israeli-Palestinian peace deal before President George W Bush leaves office in January.
Mr Olmert and Palestinian Authority President Mahmoud Abbas held talks on Tuesday and a spokesman for the outgoing prime minister said the two would continue to meet until a new government was sworn in.
Are you in Israel and are you following events? Send us your views using the postform below.
