There was no immediate claim of responsibility for the assault Wednesday night in North Sinai, where security forces are battling extremists linked to the ISIL terrorist group.
"Unidentified gunmen opened fire on security forces at El-Etlawi square in the center of El-Arish," the ministry said in a statement, referring to the North Sinai provincial capital.
A gun battle ensued in which the five policemen were killed and three conscripts were wounded, it said, AFP reported.
Security forces were searching for the attackers, the ministry said.
The region is a bastion of the ISIL-affiliated extremist group Sinai Province.
Its fighters are waging an insurgency against security forces in North Sinai, and have regularly carried out deadly attacks on policemen and soldiers.
The latest attack comes just days before the fifth anniversary of the January 25, 2011 uprising that ousted former president Hosni Mubarak.
The insurgency in North Sinai swelled after the army ousted former president Mohamed Morsi in July 2013.