The damaged Ferris wheel. Photo: Greymouth Star

Authorities are calling for witnesses to a Ferris wheel accident on the West Coast which injured three including two teenagers who plunged 12 metres.

WorkSafe is also seeking video footage as it investigates the “serious incident” at AGfest in Greymouth earlier this month.

In the October 17 accident two teenage girls fell about 12m and sustained injuries.

One girl landed on another person on the ground, injuring her as well.

One of the teenagers told Allied Media she and her friend, both aged 15, were sitting in the carriage when her friend grabbed the side bar or grate ‘‘and then it just broke off really easily’’.

‘‘We were at the top and it [the broken piece] hooked on to another piece of metal.

‘‘We thought it would break off, but the whole cart started tipping forward and we were nearly upside down.

‘‘My friend fell out — I saw her fall, I’m not sure how she landed.

‘‘Then I fell and don’t remember how I fell or landed.

‘‘I’m not sure what happened to that other girl [who was struck on the ground].’’

The girl said she had also had nightmares about the incident.

All three were assessed at hospital and later discharged.

“This was a potentially very serious incident, and it was fortunate nobody was more seriously hurt,” WorkSafe said in a statement.

Inspectors were examining the mechanical failure and circumstances leading to the fall.

They want to hear from anyone who was at AGfest that afternoon and witnessed the incident.

WorkSafe has issued a prohibition notice preventing the Ferris wheel’s further use until a competent assessor certifies that it is safe.

The Ferris wheel was being operated by Sturgeons Entertainment at the Greymouth aerodrome outdoor arena.

Senior Sergeant Mark Kirkwood said a support strut on a carriage broke.

Snr Sgt Kirkwood said the broken strut hit one of the supporting columns, causing the seat to tip forward.

The operation was immediately shut down by police and WorkSafe was notified.

‘‘The operator said he had been operating 40 years and never seen that,’’ Snr Sgt Kirkwood said.