A geopolitics expert says Israeli strategies for recovering hostages taken by Hamas could follow multiple avenues.

Israel's death toll since the attack has climbed to more than 1000, and return fire on Gaza has killed more than 900.

Democracy Project Analyst Geoffrey Miller says Israel is assembling a ground offensive, but it could take weeks to carry out.

He says Israel could also pursue other options.

"There are 5000 Palestinians in Israeli jails- they might be swapped for those at some point, or they might be used to secure a ceasefire."

LISTEN ABOVE

• Biden condemns 'sheer evil' of Hamas militants
• Live: 'It's a massacre': Hamas killed babies in Israeli village; Gaza bombardment intesifies
• Festivalgoers, children, soldiers: What we know about the people captured by Hamas
• Israel Institute of NZ urges the Government to label Hamas a terrorist organisation