Six buildings sustained damage early Thursday morning in Alexandria's Karmouz neighbourhood, possibly due to unauthorised excavations under an adjacent building.
No casualties have so far been reported.
Police have arrested one suspect, Ahmed Hassan Ali, 29, who had several clay pots – which appeared to be very old – in his possession.
Interior ministry personnel reportedly discovered a two-metre-wide and 15-metre-deep cavity under the main entrance of an adjacent building.
Alexandria governorate officials have inspected the damaged buildings and the surrounding area.
The coastal city of Alexandria has suffered a number of major building collapses within recent years.
Building collapses in Egypt are usually attributed to decaying infrastructure, local authorities' failure to carry out demolition orders, and unlicensed construction of additional floors.