Police were notified of the incident at around 7.15am this morning.
Police were at the school and inquiries were under way to determine the circumstances surrounding the email.
The schools have said there are no students onsite and police are currently present.
Both schools have closed for the day following the threat.
Al-Madinah has written on its website “Al-Madinah school is in lockdown”.
Zayed College said on its website that it was closed today following a suspicious call to Al-Madinah.
“As a matter of caution, following a suspicious call to Al-Madinah, Zayed College will be closed today.
“If your daughter or family member is currently at school, we are in full lockdown and will communicate with you as soon as we can,” Commissioner Linley Myers said.
NZ Fiji Times reported that students had received threatening emails today.
Al-Madinah School assistant principal Rizwan Hussein confirmed the situation.
The school’s principal Asin Ali told NZ Fiji Times that students had received threatening emails and were advised to stay home.
Iqra School principal Leanne Chartrand said, “we are on alert currently in the event of an emergency due to another school in South Auckland receiving threats.
“We have very good practices in place and the staff will be on alert to ensure our children stay safe.”
Ministry of Education Hautū (leader) Te Tai Raro (North) Isabel Evans said “we’re in contact with the two schools that went into lockdown and have offered our support if needed.”
Al-Madinah School offers students courses in Islamic subjects as well as complete coverage of the New Zealand Curriculum.
Zayed College for Girls is a state-integrated special character Islamic secondary school for girls Year 7 – 13.