A female member of the NSW Mounted Police Force is allegedly the mystery passenger on board a forklift in a late night drunken rampage at Australia's agricultural showcase, the Sydney Royal Easter Show.

NSW Police confirmed tonight the woman officer is being investigated as being the passenger who fled the scene after she and a woodchopper took an alcohol-fuelled joyride on the forklift, crashing through show pavilions.

The man, who was three times over the legal drinking limit, was arrested at the scene. The woman was the subject of a statewide search and her identity had remained unknown – even to the most senior police.

The female police officer, who reportedly later fled the scene after her companion was caught, is a member of the world’s oldest mounted police force.

The NSW Mounted Police annually performs the musical ride at the Easter Show, a “much loved” display of precision movements acted in time with the NSW Police Band

The drunken rampage began at around 1 am on Sunday, March 31, when the 27-year-old Queensland man and the woman allegedly took control of an onsite forklift.

A security guard spotted them driving down an avenue of the showgrounds, formerly the 2000 Sydney Olympics site, and called for them to stop, but the forklift accelerated away and crashed into steel bollards.

The guard jumped onto the forklift and removed the keys from the ignition.

The driver took off through nearby pavilions and alleyways, but was caught by the guard after a short chase.

The woman fled. Police took the driver, who is from Marian in Queensland, to a Sydney police station where he returned a breath-test reading of 0.170.

A NSW Police spokeswoman told news.com.au a “woman who is a member of a special police unit is under investigation as to the extent of her involvement” in the crime.

The NSW Mounted Police Unit’s annual display at the Sydney Royal Easter Show, according to the NSW Police website, "has received acclaim from many overseas visitors and is considered to be one of the most spectacular rides in the world”.