An Australian tourist has been arrested in the United States for an alleged drunken attack on a 68-year-old cyclist at a zombie-themed bike riding event in Florida.

Prue Elizabeth Harvey, 32, from Yamba in New South Wales, was arrested on a felony battery charge — a more serious offence than a misdemeanour because the alleged victim was aged 65 or older.

According to police, Harvey shoved Linda Malcolm off her bike as she was participating in the annual Zombie Bike Ride at Florida Keys.

A police report said Harvey told officers she was drunk and did not remember attacking Ms Malcolm — the report said Harvey was in Florida Keys for a wedding.

Ms Malcolm's daughter told police Harvey was running between the bikes in the parade and gave one family "dirty looks" before shoving her mother.

"Harvey ran past and yelled "Fall bitch!" at Malcolm," the police report said, before Harvey "pushed [Malcolm] off her bicycle knocking her to the ground".

Ms Malcolm suffered scrapes on her left knee. Her daughter chased Harvey to a church parking lot and called police.

"Harvey had no recollection of the above incident," the report said.

"She smelled strongly of an alcoholic beverage. She was at a bar earlier and was unable to recall anything she had done after 1300 hours."

In Florida, a battery charge on a person on or over the age of 65 is treated as a third degree felony instead of a misdemeanour, and is punishable by up to five years in prison and a fine of up to $US5,000 ($6,430).

This year's Zombie Bike Ride attracted more than 6,000 participants, local media reported. ( Florida Keys News Bureau via AP )

ABC/AP