The terrifying moment a six-year-old's seatbelt snapped on a rollercoaster.

One minute, loving father Delbert Latham was filming a rollercoaster ride beside his son. The next? Every parent’s worst nightmare.

In a terrifying ordeal, six-year-old Kaysen’s seatbelt released halfway through the Wonderland Park ride, sending his little body to the bottom of the cart.

Luckily for the little guy, dad was there to reach down and pull him up, and clutched  tightly to his side until they returned to the ground.

In a public Facebook post with the video – which was originally intended for his wife – Delbert told friends and family about the scary experience.

“Scary moment for the Latham family tonight at #Wonderland our seatbelt came apart on the mousetrap and Kaysen slid to the bottom of the floor board and I had to grab him and pull him back up and hold him for the rest of the ride.”

To make matters worse, Delbert explained that the malfunctioning seatbelt was already known to a staff member, who had heard about prior safety incidents.

“What makes it worse is when I told the guy at the end of the ride he stated that he knew that had happened sometimes! Really it’s already happens (sic) and you continue to let people ride??!!”

"The guy at the end of the ride said he knew that had happened sometimes!" (Image: Facebook)

Speaking to KFDA-TV, Delbert said the ride operator was nonchalant about the safety nightmare.

"He stated to me that 'oh yeah, I'm sorry about that. That's been happening sometimes'... That made me more angry obviously.

"I told him that's not acceptable to know that something is messing up and still let people on a ride."

The amusement park, which is a popular attraction in Amarillo Texas, publicly addressed concerns, thanking Delbert for his efforts to bring the matter to their attention.

"Wonderland Amusement Park has taken great strides over the past 65 years to ensure the safety of our visitors at all times, therefore we were extremely concerned to hear about the experience of Mr. Latham and his six-year-old son over the weekend.

"The seatbelt in the last car on the Mouse Trap roller coaster reportedly came loose creating a very scary situation for the family. Mr. Latham immediately informed the ride operator, found a member of management and reached out through a private social media message.

"We appreciate his diligence in quickly bringing this to our attention.

"Wonderland immediately reached back out to Mr. Latham the evening it happened and promptly removed the back cart from the ride and ensured all other seatbelts were in proper working order.

"The Mouse Trap was back in full operation on Saturday.

"This particular ride was originally built without seatbelts, but Wonderland later added belts as an extra safety measure.

"The Park's Safety and Maintenance Team is tasked with conducting daily inspections on every Park ride to ensure the safety of Park goers."