Fringe patron, Michael Costalos was escorted out of venue for bringing his service dog

Police are investigating an incident that saw a Fringe patron escorted off the venue for bringing his service dog.

Police are investigating after a patron was escorted out of the Garden of Unearthly Delights after a security guard allegedly grabbed him by the throat for bringing his service animal into the venue.

Michael Costalos who suffers with post-traumatic stress disorder entered the venue at 6.50pm for a 7pm show with his Maltese Shih tzu, Finn.

The man can be seen being pulled out of the venue by security. Picture: 7NEWS

It is understood his dog was not recognised as a service animal. Picture: 7NEWS

After showing three different security guards the relevant paperwork explaining the legitimacy of his service dog he was confronted again by a fourth guard who did not accept it.

Videos have emerged from witnesses who are shocked by securities handling of the situation.

The Garden of Unearthly Delights declined to comment.