THE VRC Oaks Day meeting at Flemington was marred by an ugly mounting yard incident when a strapper was allegedly assaulted by a stablehand from the powerful Darley Stud, owned by Sheikh Mohammed bin Rashid Al Maktoum.

FAIRFAX MEDIA report that in an unsavoury incident that took some of the gloss off the carnival's traditional Ladies' Day meeting, the strapper was awaiting the return of her winning horse Black Cash after the race five Subzero Challenge.

Footage aired on Channel Seven on Thursday night showed the woman speaking to a man in the mounting yard before he appeared to swing a right hand and make contact with her face. Bruising was clear on the woman's face after the incident.

Chief steward Terry Bailey said a police investigation and a Racing Victoria inquiry were launched immediately following the incident.

''I watched the incident unfold. A strapper was in the mounting yard, and an employee of the Peter Snowden team came up behind her and king kit her and then ran away in the direction of the horse stalls,'' Bailey said.

''The woman is currently being treated on course, and police have apprehended the offender.

''Victoria Police are currently questioning him as well as he is a registered stablehand. I can tell you the woman was conscious when doctors examined her moments after the incident.''

Police have confirmed that a 31-year-old Ascot Vale man is in custody in relation to the alleged assault. A Victoria Police spokeswoman said it was believed that both parties were known to each other, and that the alleged victim was a 27-year-old from NSW. 

''It's a police matter and we're not making any comment,'' Darley's general manager Henry Plumptre said.Bailey said all parties, including members of Snowden's team, were disappointed by the incident. ''It's not needed here on the racecourse,'' he said.

"The police want that footage for possible prosecution.''Bailey confirmed the woman was treated by medical staff.  ''She's got some bruising. But it was probably more shock and stress than anything else,'' he said.