The 78-year-old Amin, whose 1971-79 regime was one of the bloodiest in African history, reportedly remains in a coma after four days on a life support machine.
The Ugandan political party he ousted in 1971 is among those calling for him to be allowed to return from Saudi Arabia to die in his homeland.
An international human rights group has voiced regret that he may die now at liberty instead of in prison, the BBC reported.
"We regret that Idi Amin is dying without meeting justice for his crimes," said Reed Brody, at Human Rights Watch.
An aide to President Yoweri Museveni said any Ugandan could return.
"All Ugandans can return, including Amin," John Nagenda said. "However if they return, they will be subject to the full force of the law."