A MYSTERY malfunction in one of the entry gates at Dalby Forest was revealed to have been caused by a sleeping mouse.

Forestry Commission staff posted a picture of the critter curled up on the vehicle barrier's warm circuitboards on Instagram.

The wood mouse had worked its way into the circuitboard housing and was discovered by staff when they investigated why the barrier was "playing up".

A staff member at Dalby Forest visitor centre said the mouse was removed from the barrier and released into woods nearby.