A levee Charleville can bank on

Suncorp has begun cutting the cost of premiums for residents of a flood-prone region of Queensland, signalling that benefits of mitigation efforts will flow through to local communities.

Mark Milliner, chief executive of Suncorp's personal insurance division, will travel to Charleville on Wednesday to announce customers in the outback town will see average home and contents premiums fall by $400 to about $990, next time they renew their policies.

The reduction follows the completion of a $20 million levee and diversion project that reduced risks of inundation for the town. Without it average premiums would be running at $3000 a year, pricing insurance out of reach of most residents.

Suncorp sparked anger in 2012 when it denied insurance to nearby towns of Roma and Emerald after three major floods in as many years to highlight the heavy costs of not investing in mitigation efforts. Existing customers reportedly complained that premiums had risen as much as tenfold.

"We paid out over $100 million in claims and governments would have paid that much and more," Mr Milliner said.

This year the company said Roma had been discussing the construction of a levee since 2005 with the cost between $2 million and $10 million.

In February the federal government pledged $7 million and the Queensland government $13 million to build a levee at Roma.

The Greens are going to this election pledging to lift annual federal spending on mitigation for floods, fires and other disasters from $50 million to $350 million, with the increase paid for by a levy on thermal coal exports.