Dog the Bounty Hunter allegedly shoved a teenager at the airport -- at least that's what the teen's father claims -- but Dog's side denies the assault and says the kid was verbally abusive.
A police report was filed in Denver ... by the father who claims he and his family ran into Dog and Beth Chapman at the Denver airport last Friday. He says his 17-year-old son approached Dog and asked for a photo. He claims Dog got upset and put a closed fist into the kid's chest and pushed him away.
The father got pissed and got into a verbal altercation with Dog. Beth eventually calmed things down, and she and Dog got on an elevator.
A source close to Dog says when the teen walked up to Dog, he said, "I have a bounty on my head, what are you gonna do about it motherf***er?" Dog admittedly told the kid to get back and he didn't want to deal with it ... because his wife is sick.
We're told the teen's response was, "Tell that fat bitch to get out of her chair. I'll cut her in half." Beth was in a wheelchair at the time.
Dog and Beth had just flown to Denver from L.A. ... where she had emergency surgery last week for a throat blockage. Doctors discovered her cancer had returned.
According to a law enforcement source, cops are looking into the incident as an alleged assault ... but our Dog sources tell us he plans on filing a report for harassment against the kid and his dad.