"Anyone who digs or prepares or uses a road, a passage, or an underground tunnel in the country's border areas with the purpose of connecting with a foreign entity or state, its citizens or residents… will face life in prison," according to the decree.
The document stipulates the same punishment on those who are aware of such illegal routes and fail to inform the authorities of them. Life imprisonment in Egypt amounts to 25 years behind bars.
The decree is part of the army's efforts to destroy the tunnels that connect the restive Sinai Peninsula to the Gaza Strip; the military has been demolishing the tunnels since the ouster of Islamist President Mohamed Morsi in July 2013.
Cairo points the finger at the Palestinian movement Hamas for using the tunnels to enter Egypt in order to support jihadists who have already killed at least 33 security personnel in attacks in the Sinai Peninsula.
In North Sinai, the attacks were masterminded by the "The Sinai Province" group, formerly known as Ansar Beit al-Maqdis.