File - Israel's Foreign Minister Israel Katz. AFP
Defence Minister Israel Katz said the operation would be conducted under an "international mechanism" led by the United States, sponsor of the three-day-old Gaza ceasefire.
"Israel's great challenge after the hostage release phase will be the destruction of all Hamas tunnels in Gaza," Katz said in a statement.
"I have ordered the army to prepare to carry out this mission."
Katz said the remainder of Hamas tunnels would be destroyed under the framework of Hamas's disarming and demilitarisation, foreseen in the next stages of the US-backed ceasefire plan.
Hamas has agreed to the first stage of the plan, which led to a ceasefire on Friday and on Monday should see the release of 48 Israeli captives, living and dead.
In exchange, Israel is expected to release 250 prisoners, including some serving life sentences, and 1,700 Gazans detained by the Israeli military.
But Hamas has resisted calls to disarm, and on Sunday senior official Hossam Badran told AFP the second phase of the US plan "contains many complexities and difficulties".
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