The controversial law, published in the government's official gazette on Sunday, sets a minimum fine of 200,000 pounds (about $25,000) and a maximum of 500,000 pounds for anyone who strays from government statements in publishing or spreading "false" reports on attacks or security operations against armed fighters.
Critics say the steep fines may shut down smaller newspapers, and deter larger ones from independently reporting on attacks and operations against armed fighters.
It also shields those applying it, such as the military and police, from legal ramifications for the proportionate use of force "in performing their duties." The law also seeks prison terms for those found guilty of "inciting, or prepared to incite, directly or indirectly, a terrorist act".
Dalia Fahmy, an assistant professor at Long Island University and a member of the Egyptian Rule of Law Association, said that any media "that defies the national narrative, will be fined."
The law here is a system that is not protecting the citizenry, but rather protecting the state ... it is becoming indicative of the consolidation of power in the hands of the executive," Fahmy told Al Jazeera from New York.
Sisi had promised a tougher legal system in July, after a car bomb attack that killed the top public prosecutor, the highest level state official to be killed in years.
Forming or leading a group deemed a "terrorist entity" by the government will be punishable by death or life in prison.
Membership in such a group will carry up to 10 years in jail.
Financing "terrorist groups" will also carry a penalty of life in prison, which in Egypt is 25 years. Inciting violence, which includes "promoting ideas that call for violence" will lead to between five and seven years in jail, as will creating or using websites that spread such ideas
Journalists will be fined for contradicting the authorities' version of any "terrorist" attack.
Egypt is facing an increasing violence in North Sinai, where one armed group has pledged allegiance to Islamic State in Iraq and the Levant (ISIL) terrorist group. Cairo and other cities have also witnessed attacks.
Hundreds of members of the Muslim Brotherhood have been sentenced to death in mass trials since Sisi, a former army chief, overthrew president Mohamed Morsi in July 2013.
Many of them have won retrials, and Morsi himself, sentenced to death last June, has appealed his verdict.
At least 1,400 people, many of them supporters of Morsi, were killed in a crackdown on protests after his overthrow.
Morsi's Muslim Brotherhood group, once the most influential grassroots organization in the country, has been blacklisted as a "terrorist" organization.