The decree said the armed forces and police should take all necessary measures "to confront the threats and funding of terrorism and maintain security throughout the country".
It was published Saturday in the official gazette.
The state of emergency has been in place since April 2017 after bombings struck two Coptic Christian churches on Palm Sunday, later claimed by the Islamic State terror group.
In February, Egypt began a large-scale anti-militant operation, mainly in the volatile Sinai Peninsula, the epicentre of a years-long Islamic insurgency.
It involves land, sea and air forces and covers parts of Egypt's Nile Delta and the Western Desert, along the porous border with Libya.
You can hear Premier's Eno Adeogun's documentary on the anniversary of the Palm Sunday bombings in Egypt here:
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