"It's difficult to say exactly how much the final amount will be," Sylvia Gaeumann, a spokeswoman for the company told AFP.

"It could be a bit higher or a bit lower (but) usually our estimates are good."

She explained that the actual amount of claims was higher than $700 million, but that the insurer was partially shielded through reinsurance coverage, which had kicked in.

This however meant that Zurich Insurance Group would need to renew its reinsurance contract, which was expected to cost an extra $58 million before tax, the company said.

The estimated costs would be recorded in the company's fourth quarter and full-year results, which will be published on February 14, it said in a statement.

Zurich Insurance Group was not hit so hard as its compatriot Swiss Re, which late last month put its exposure to Sandy at about $900 million.

Earlier this month, US President Barack Obama asked for $60.4 billion in emergency funds to repair devastation after the storm, which flooded the New York subway system and knocked out electricity for hundreds of thousands of people.

The floods and wind also destroyed or damaged hundreds of thousands of homes, schools and hospitals, and created chaos in fuel supplies after refineries and gas stations were damaged.