Families of two Queenslanders missing for four days have serious concerns for their safety

Two people have been missing from a small southeast Queensland town for five days.

Lee Powell and Kathleen Hockey, both in their 20s, were last seen at Nanango in the South Burnett Region, northwest of Brisbane, on Sunday night.

Their families hold serious concerns for their safety as they both have medical conditions.

It's believed the pair are travelling in a white Ford utility on the Sunshine Coast.

Ms Hockey is described as Asian, about 153cm tall and has black hair, while Mr Powell is Caucasian, about 170cm tall and has light brown hair.