Red Bull team principal Christian Horner is at the center of an investigation ... after a staffer within the Formula One organization accused the longtime boss of alleged inappropriate behavior.
The energy drink giant released a statement on Monday ... saying, "After being made aware of certain recent allegations, the company launched an independent investigation."
Red Bull added the probe is being conducted by an outside party ... and it takes the situation "extremely seriously."
Horner -- who has been with the organization since it joined the grid in 2005 -- has denied the allegations .