Having interrogated him once before in October, the police said Sharon would be questioned again at his Jerusalem home on Thursday.
The re-questioning comes after last month's indictment of property developer David Appel on charges of trying to bribe Sharon.
If Sharon were to be charged himself, political commentators say he would have no choice but to resign from office.
Appel was indicted for trying to bribe then foreign minister Sharon though his son Gilad, along with Deputy Prime Minister Ehud Olmert, then mayor of Jerusalem, in exchange for their help in securing a major Greek property deal.
Sharon has until now refused to answer specific questions about money given to his son by Appel, and recently said he had nothing to do with the scandal, which dates back to 1998.
At the time, Appel, a key figure behind the scenes in Likud, was planning a huge tourism project on a Greek island which needed authorisation from Athens.
Appel tried to secure the help of Sharon and Olmert, both of whom were candidates for the Likud leadership, in exchange for financing their respective campaigns, his indictment said.
Several high-level officials at the justice ministry, including state prosecutor Edna Arbel, have openly demanded that Sharon be indicted too.