Monday's decision came a day after Israel's chief prosecutor formally recommended putting Sharon on trial for allegedly taking bribes from a businessman who was pursuing a Greek island development scheme that ultimately flopped.
In the other case, prosecutors believe Sharon's two sons used a $1.5 million loan from a South African businessman as collateral to repay alleged illicit contributions to a Sharon election campaign. Foreign funding of political campaigns is illegal in Israel.
Sharon's son Gilad, whom prosecutors said was in control of the documents, will comply with the high court decision, said his lawyer. Gilad had refused for months to hand over documents to police investigators.
Months before ruling
Attorney General Menachem Mazuz will have the final say on whether to indict the 76-year-old Sharon. Justice Ministry sources said it could take up to two months for him to rule in the Greek island affair.
Palestinians fear a unilateral
pullout will leave them nothing
At issue in the "Greek Island Affair" is an attempt by real estate developer David Appel to promote a tourism project on a Greek island in 1999, at a time when Sharon was foreign minister.
Appel hired Gilad Sharon as an adviser and allegedly paid him hundreds of thousands of dollars.
At the time, investigators were wiretapping Appel, the Haaretz daily said on Monday. According to one tape, Appel told the elder Sharon in one conversation that "your son is going to earn a lot of money."
At a later point in the conversation, Sharon said: "The island is in our hands."
Sharon has denied any wrongdoing. But the legal storm enveloping Sharon could hinder his efforts to push through his so-called "disengagement" plan from the occupied Gaza Strip.
Sharon hopes to win US President George Bush's approval for the plan at a critical meeting on 14 April in Washington.
Meanwhile, Israeli Deputy Prime Minister Ehud Olmert said that Sharon would remain in power despite growing pressure over the most recent scandal.
National Infrastructure Minister Yosef Paritzky said on Sunday that Sharon should step down if he was indicted. His call was echoed by several members of the opposition.