Security staff have detained a teenager who ran across the track during the last race at Eagle Farm.

Almost the entire field had passed when the man ran across the straight near the 200m mark on Saturday.

There was still one horse coming at the time but it missed the man who was held by security staff in the infield until police were called to detain the 19-year-old.

"Apparently, his mates dared him to do it," BRC chairman Neville Bell said.

"I hope they are going to pay the fine. It is a stupid thing and highly dangerous to do."