A giant animatronic T Rex has caught fire at a US theme park, creating a nightmarish spectacle.

An electrical fire triggered the flames which lit up the Tyrannosaurus rex at the Royal Gorge Dinosaur Experience.

In a Facebook post, the Colorado park said the dinosaur was now "extinct".

"Holy smokes! We always knew T-Rex had a temper but today he blew his top," it said.

"There was an unfortunate [and rare] electrical issue with our mighty T Rex and he is no longer. You might even say … extinct."

The fire reduced the T Rex to a metal skeleton. ( Facebook: Royal Gorge Dinosaur Experience )

Nobody was hurt in the incident, which the park described as "isolated and unexpected".

"We are incredibly proud of our team for the way they efficiently and quickly handled this situation and kept our guests safe," it said.

"All in all, this happened very quickly and we are a little shaken but we are operating business as mostly usual."

The park said it was "planning to have a replacement T Rex before summer".

ABC/Reuters