The sources said authorities had confiscated the outer shells of 60 rockets from a metal workshop in the Sinai town of Sheikh Zuwayed, near the closed Rafah border crossing with Gaza.
Those held include the owner of the workshop and other workers and drivers who are accused of taking part in a scheme to manufacture rocket parts and send them to Hamas in Gaza.
The sources did not specify whom the rocket parts were intended for in the Strip.
Earlier this week al-Jazeera reported that Egypt arrested 50 Egyptians, Palestinians, Lebanese, and Israeli Arabs for alleged ties to terror groups.
A prominent Islamist lawyer told the news channel that the detainees were suspected of financial aid to Hamas and membership to Hizbullah.