Police are questioning two men believed to be the last people to see Queensland teenager Jayde Kendall before she disappeared outside a high school on Friday afternoon.

A passer-by found an item belonging to the missing teen on a service road off the Warrego Highway in Walloon, more than 40km from where she was last seen outside Lockyer District High School, getting into a red car around 3.20pm with a teenage boy known to her.

Detective Inspector Isherwood said police and SES volunteers were now searching the area the item was discovered, as well as a nearby dam.

"We’re hopeful that she has just run away, but we’ve got to be realistic – the fact that she has not been in contact with anyone is of some concern for us," he said.

Police said the 16-year-old's family had been in regular contact with authorities, desperate for any update on Jayde's whereabouts.

Police are appealing for help locating missing teenager Jayde Kendall. (Supplied) (Supplied)

"There is no doubt she got into the car of her own free will," Det. Insp. Isherwood said.

Det. Insp. Isherwood also said police interviewed the teenage boy and are investigating his version of events, and while he is a person of interest, he is not a suspect.

Police believe Jayde spent a few hours with the teenager but do not know where she went after that.

Friends and family alerted police she was missing when she failed to turn up to work at McDonald's later that day.

Police said Jayde's father was "particularly distraught, having lost his wife to cancer some years ago".

Jayde is described as Caucasian, 155cm tall with a medium build, brown hair, and green eyes.

Her family and friends have created the Help Find Jayde Facebook page and the #HelpFindJayde hashtag in order to spread the word.

However, police slammed speculation on social media regarding Jayde's whereabouts, saying it was not helpful to her family or police and she is "a decent girl".

Det. Insp. Isherwood said comments made were "absolute garbage" and "all they are doing is demeaning her and her family".