Mr Sharon was a giant of the Israeli military and political scene, but courted controversy throughout his long career.
He was being treated at the Sheba Medical Center outside Tel Aviv. A hospital statement is expected shortly.
On Thursday doctors announced that Mr Sharon’s condition had deteriorated.
The 85-year-old, who became PM in 2001, was suffering from a malfunction of several organs including the kidneys, they said.
He had been in a persistent vegetative state since a stroke in 2006.