Suncorp and IAG have raised their outlooks for financial-year natural peril costs after claims were elevated by the SA and Victorian storms that have been declared a catastrophe by the Insurance Council of Australia (ICA).

IAG increased its full-year natural perils forecast by 36.6% to $1.045 billion and lowered its reported margin guidance range to 10-12% from 13.5-15.5% previously.

The insurer says its net cost for the storms catastrophe is anticipated to be $169 million, the maximum retention for a first loss under its catastrophe program.

The full-year figure includes $535 million for the first four months. In addition to the recent storms, that comprises $204 million for the September quarter, $142 million for other weather events across eastern Australia in October and $20 million for attritional events last month.

Suncorp expects natural hazard costs of $1.105-$1.130 billion for the fiscal year, which is $125-150 million above the previously announced $980 million allowance, divided equally between the first and second halves.

Including the latest storms, there have been six declared weather events in October, Suncorp says, while costs for the half have also been inflated by the Victorian earthquake and other storms in Australia and New Zealand.

The insurer expects the total cost from the recent storms event could reach $225-250 million, leading to a revised year-to-date estimate for natural hazard costs of $597-702 million.