The Insurance Council of Australia (ICA) has declared flooding around Forbes in central west NSW a catastrophe, after the Lachlan River inundated properties at the weekend.

CEO Rob Whelan says the extent of residential, business and crop damage is not yet clear and it will take several weeks to be known, but the industry had escalated its response to help policyholders.

“Early reports indicate the region has suffered extensive crop losses, while about 100 businesses and homes may also have been affected by flooding,” he said.

“It’s likely that insurance losses will be in the tens of millions of dollars.”

ICA has established an industry taskforce, activated a disaster hotline for policyholders and has mobilised staff to work directly with local services and people.

Several insurers have started setting up disaster response teams in the Forbes region, ICA says.

Premier Mike Baird travelled to the region today to assess the situation after evacuation orders were issued.

The Lachlan River at Forbes Iron Bridge peaked at 10.67m on Sunday night, with the flood exceeding a similar event in August 1990, according to the Bureau of Meteorology.

Wet weather is forecast across already drenched areas of NSW and Victoria later this week, and water levels in the Forbes area are expected to stay elevated for several days.

Australia this year recorded its second-wettest winter since records began in 1900, and the four months from May to August were the wettest on record.

It follows the double impact of Pacific and Indian Ocean temperature change patterns, which are each typically associated with increased eastern Australian rainfall.

The breakdown of an El Nino weather pattern to the east has come at the same time as a negative Indian Ocean Dipole phase to the west.