Ousted Egyptian president Hosni Mubarak has slipped in the bathroom in the prison where is serving a life sentence, hitting his head, according to a security official, Belfast Telegraph said.

The ailing Mubarak, 84, was treated in Cairo's Tora prison for head injuries and a chest bruise. The official added that Mubarak had also slipped two months ago, but did not injure himself.

The report comes at a particularly tense moment in the transition that has followed Mubarak's 2011 overthrow, as millions of Egyptians vote in a highly contentious referendum on a draft constitution written by a mostly Islamist panel.

Mubarak was convicted of failing to stop killings of protesters during the uprising. There have been conflicting reports about his health.