Shares in Dreamworld operator Ardent Leisure continued to tumble on Wednesday in the wake of Tuesday’s fatal accident at the Gold Coast theme park.

Ardent Leisure chief executive Deborah Thomas flew to the Gold Coast on Wednesday, a day before she and the Ardent board face investors at the company’s annual general meeting in Sydney.

As police continued their investigation into the accident that killed four people on a water raft ride, Ardent shares dropped 15 per cent to $2.00, a day after losing 7.8 per cent in the hour after the tragedy.

The shares have dropped by 67 cents since the accident, wiping more than $310 million from the company’s market capitalisation, to almost $940 million.

Dreamworld remains closed and police have warned their investigations into the accident could take some time.

Emergency services personnel at the scene of the accident at Dreamworld on Tuesday. Photo: AAP

The Australian Workers Union, which represents Dreamworld staff, has said it took safety concerns to Ardent as far back as April 2015, and even submitted right-to-information requests with the division of Workplace Health and Safety.

A spokesperson for Dreamworld said specifics of what occurred in the accident are subject to a coronial investigation but confirmed that the Thunder River ride involved had completed its annual safety engineering inspection on September 29.

Dreamworld’s operator is also considering a memorial day to reopen the park later in the week, with scaled-down operations and fundraising for victims’ families.

Ms Thomas, who is expected to speak about the tragedy after Thursday’s AGM, has not yet spoken to families of the victims but the company has sought to make contact through Queensland Police.

Forager Funds senior equities analyst Daniel Mueller said the indefinite closure period made it difficult to estimate a financial impact on Ardent.

Ardent’s theme parks, which also includes the neighbouring WhiteWater World, accounted for 15.6 per cent of its total revenue in the 2015/16 financial year, and 22.8 per cent of earnings.

“They are a diversified group and the main driver of the business is their US family entertainment centres,” Mr Mueller said.

Fellow theme park operator Village Roadshow has also been dragged lower, dropping 23 cents, or 4.4 per cent, to $5.02.

-AAP