BEIT-UL-MOQADDAS -- Corruption allegations linked for the first time to Zionist Prime Minister Ariel Sharon have eroded his support ahead of the January 28 general election, a leading pollster said on Wednesday.

The latest scandal to hit the right-wing Likud Party has drawn calls for Sharon's resignation from his Labor Party challenger, Amram Mitzna, despite denials of wrongdoing from the prime minister's aides.

Though Sharon remains the frontrunner, a survey shows almost a third of voters think the corruption allegations disqualify him from serving as prime minister, said Avi Degani, head of the Geocartography Knowledge Group.

Adding to Sharon's worries, the poll suggested 16 percent of his own Likud Party members had lost confidence in him. Another probe into vote-buying in the party's December primary ballot has already cut into its once-commanding lead.

The newest scandal, dubbed "Sharongate" by the media, was triggered by a report on Tuesday in the left-wing Ha'aretz newspaper of funding irregularities in Sharon's 1999 Likud election campaign.

The article said Israeli authorities requested assistance from their South African counterparts. The probe concerned an alleged loan of $1.5 million to Sharon's family from a South African businessman. Israeli law bans political funding from abroad.

The money, according to the report, was put up as collateral for a loan used to cover the return of illegal campaign funds, which Sharon earlier said he had paid back by taking out a mortgage on his ranch.

Israeli police spokesman Gil Kleiman confirmed police had opened an investigation into alleged improprieties in funding arranged by Sharon's people in 1999 but declined to give names of those under suspicion.

A notorious figure Sharon has been accused of war crimes. He is known as the butcher of Sabra and Shatilla massacre in Southern Lebanon in 1982 when he was serving as Zionist defense minister.