Wildfires in Texas and surrounding states have destroyed more than 400,000 hectares and claimed at least seven lives.

Texas A&M Forest Service says the Perryton blaze, which burned more than 128,000 hectares, is the third-largest wildfire in the state’s history.

Wildfires have also hit parts of Kansas, Oklahoma and Colorado.

In Kansas a state of disaster was declared as fire crews tackled a blaze affecting about 253,000 hectares.

More than 200,000 hectares was burned in Clark County and Comanche County, making it the most widespread single fire on record in Kansas.

Most of the damage has been to farming and agricultural assets.

Catastrophe modeller Impact Forecasting expects a large gap between overall economic loss and insured losses, since most of the damaged agricultural and farming infrastructure is not covered.

The Aon Benfield subsidiary estimates the economic loss from the wildfires, including earlier blazes in Florida, at about $US100 million ($133 million).