Austria is probing Vienna's Spanish Riding School after claims that the famed school mistreated some of its Lipizzaner horses, the government said Tuesday.

It is the latest headache to hit the classical dressage institution whose managing director was let go in September over alleged expense irregularities.

Public broadcaster ORF reported late Monday that employees described mistreatment of young horses in a 2023 internal survey.

"I take these allegations very seriously and have therefore immediately commissioned the internal audit to conduct an investigation," said agriculture and environment minister Norbert Totschnig, whose ministry is in charge of the school.

The Spanish Riding School -- which was founded in 1565 -- said it "firmly" rejected the allegations of animal cruelty, saying "there has never been any mistreatment of our horses".

"The well-being of our Lipizzaner horses is our top priority," it said in a statement sent to AFP.

"Individual perceptions expressed in the 2023 employee survey were taken seriously, reviewed, and incorporated into the existing quality and animal welfare processes," it added.

The UNESCO-recognised school, which is globally renowned for its white Lipizzaner stallions, is to appoint a new supervisory board this week after a management shakeup.

The school breeds its own Lipizzaners, which are guided by straight-backed riders in tailcoats to canter and pirouette to the sound of music.

The lineage of the Lipizzans dates back to the 16th century, when they were first bred by the Habsburg monarchy.

The breed is a cross between Spanish, Arabic and Berber horses.