As New Zealand's largest trading partner, it is expected there will initially be some disruption to exports in the weeks ahead, but there will be some positives for New Zealand food suppliers and large companies, such as Fletcher Building and civil contractor Fulton Hogan, once rebuilding gets under way.
Expectations of the number of flood-affected homes in Brisbane alone yesterday rose sharply from 9000 to 20,000 then up to 40,000 homes in 80 suburbs, while 6000 commercial premises might be affected, according to Brisbane's Courier Mail.
With 75% of the Sunshine State declared a disaster zone, earlier estimates of damage and clean-up costs have more than quadrupled in some cases - and further rain is forecast across several states in coming days.
Flash flood alerts were posted yesterday.
While Queensland's mining sector has been hardest hit, with its coal sector alone reported to be losing $A480 million a week, the economic impact of the floods has affected agriculture, construction, transport, tourism and the retail sectors.
Craigs Investment Partners broker Peter McIntyre said estimates of the loss of gross domestic product had already been revised several times, and were now in a range of 0.3-0.75 percentage points.
Initially, before the flash floods which hit Toowoomba then those which hit Brisbane on Tuesday and yesterday, the Insurance Council of Australia, representing general insurers, said early estimates were that insurers would have to pay out $150 million from 4300 claims.
However, Mr McIntyre said, insurer SunCorp Group announced yesterday that its claims alone were likely to top $A200 million.
He warned that while disruption to mining operations was making headlines, the effects on tourism operations in Australia "could become a major problem", depending on the extent of damage, cancellations and amount of insurance carried by operators.
While Bank of Queensland stock was down 4% to $A9.57 yesterday, with concerns over its mortgage liabilities, insurance stock was not hit as hard because most had reinsured elsewhere, in order to spread their risk, Mr McIntyre said.
Forsyth Barr broker Suzanne Kinnaird and Mr McIntyre both said Fletcher Building, which was overseeing the rebuilding work in Christchurch, could see some short-term loss of trade in Australia, but pick up a lot of work around Queensland, once repairs got under way, as could Fulton Hogan.
The Australian Government has said the economic toll would be about $A10 billion in lost revenue and clean-up costs.
About $A17 million has been paid out so far to 10,000 small business owners, homeowners and farmers.
Queensland is one of the world's largest exporters of premium hard coking coal, a key ingredient in steel manufacturing, and some of its biggest producers have suspended sales contracts and production runs until waters recede, including Anglo American, Aquila Resources, Vale, Macarthur Coal, Rio Tinto, Wesfarmers and Xstrata.
Those mines are either fully or partially under "force majeure", which releases them from supply obligations.
Before the worst of the flooding this week, several miners had downgraded earning expectations for the quarter from the onset of flood problems in early December.
Steel manufacturers around the world have been scrambling to secure hard coking coal in recent weeks since the flooding began about month ago.
Mr McIntyre said futures markets were likely to become volatile in the weeks ahead and coking coal prices were already heading from $US220 towards a range of $US270 to $US300.
Reuters reported that Australia's wheat, sugar and cotton exports are expected to be hit by flooding, while fertiliser makers might also be hurt by reduced sales.
Mr McIntyre said there was rising concern that winter crops, including wheat, might be hard hit later in the week in South Australia, Victoria and New South Wales with forecasts of up to 75mm of rain.
Supermarket operators Wesfarmers and Woolworths face logistical issues getting produce into affected areas and Woolworths said as many as 47 of its stores were affected.
Soft drinks bottler Coca-Cola Amatil warned a week ago that wet weather and a cooler summer would affect its earnings, while surfwear maker Billabong cut profit forecasts in December, due to the wet weather.
