The injured policemen were transferred to a nearby hospital while security forces combed the area for the attackers, the Interior Ministry said in a statement.
Three policemen have been killed and eight others injured in Egypt after the police vehicle was attacked by a rocket-propelled grenade in Shiekh Zwayed, it said without specifying the timing of the attack.
Egypt's North Sinai has witnessed many violent attacks by militants since the January, 2011 revolution that toppled the ex-president Hosni Mubarak.
Over 700 security personnel have been reported killed since then.
The military has launched security campaigns in the area, arrested suspects and demolished houses that belong to terrorists, including those facilitating tunnels leading to the Gaza Strip.
