An off-duty police officer is under investigation after he allegedly headbutted a 14-year-old boy outside of a fast food chain.

Footage captured outside Dalby McDonald’s early on Sunday morning shows the moment the teenager confronted the constable.

It is believed the teenage boy questioned the off-duty officer’s authority and questioned whether he had a badge.

“What badge have I got right now? Which one of you said that?” the officer yelled.

One of the teens then allegedly pushed the officer.