Two road trains have been involved in a head-on crash on the Great Northern Highway south of Derby.

Police say one of the trucks was carrying cattle and caught on fire.

A number of animals have been killed or had to be put down.

The driver of one of the trucks suffered head and chest injuries, it is believed the second driver was not seriously injured.

The crash happened about 10 kilometres from the Willare Bridge bridge and is causing traffic delays on the highway.