Israeli military intelligence claims Yasser Arafat has amassed a personal fortune of €1.3bn.
But the claim is being dismissed by Palestinian Authority officials as an attempt to discredit their leader.
Mr Arafat allegedly lives frugally, but there have been reports in recent years he has funnelled hundreds of millions of pounds into bank accounts overseas.
It has been suggested Mr Arafat would use the money if forced to flee Palestinian areas.
In a report to international donors last year, Mr Arafat acknowledged the existence of a multimillion-dollar slush fund. For years, he directly controlled income from Palestinian Authority monopolies over cement and gasoline.
Major General Aharon Zeevi, Israel's chief of military intelligence, told parliament's Defence and Foreign Affairs Committee the Palestinian leader was worth about $1.3bn (€1.31bn).
The figure is based on estimates by military intelligence.