Dr. Moaiya Hassanein says their bodies were retrieved by Egyptian officials following Tuesday's collapse.
Dozens of tunnels snake under the border. They are used by Gazans to smuggle in goods — from cows, to concrete and computers — that have become scarce or forbidden under a two-year-old blockade.
Israel and Egypt imposed the embargo after Hamas militants took power in June 2007.
Israel has bombed the tunnels to try to halt weapons smuggling, making them extremely dangerous to use. Egypt has started construction to block the tunnels.
Hassanein says around 130 Gazans have been killed in tunnel collapses since the blockade began.