The exam in applied mathematics would instead be held next Saturday, it said, and other tests in geology, history, and pure mathematics were rescheduled.
The prosecutor’s office said on Sunday that the state security prosecution would handle the issue as it affected “the state’s highest interests”.
The latest case comes after Education Minister El-Helaly el-Sherbeeny said this month that the government would punish anyone involved in leaking exam papers after answers to tests appeared online.
Sherbeeny said previously that those found guilty of cheating or of leaking tests could be fined up to 50,000 Egyptian pounds ($5,600, 4,900 euros) and face jail terms of up to three years.
He spoke days after a religious studies test also had to be rescheduled when answers were leaked online just 90 minutes before students were due to sit the exam.
Several Facebook pages that have shared exam answers say they are doing so to push for high school reform, including raising teachers’ wages and upgrading outdated curricula.
The interior ministry has reported arresting several people — including education ministry officials — over the leaks.
The high school education system is frequently criticised in Egypt and is widely seen as corrupt, with the wealthy and well-connected allegedly receiving preferential treatment.