Prosecutors had filed three charges under the Work Health and Safety Act that carry a combined maximum penalty of A$4.5 million ($3.22 million) in the Brisbane Magistrates Court.

"We won't be providing any formal statement today ... given that the matter is before the court we won't be commenting any further," Ardent spokesman Paul Callander told Reuters by telephone.

The accident at the Dreamworld theme park on the Gold Coast, which killed four people, was referred to prosecutors earlier this year after a coronial inquiry found a series of failings at the venue in relation to safety checks.

Two men and two women died almost instantly when their raft collided with an empty raft, flipping it onto the mechanical ramp of the Thunder River Rapids Ride. Two children also on the raft were thrown to safety.

($1 = 1.3965 Australian dollars)

(Reporting by Renju Jose)