The Dreamworld theme park in Queensland, where four people died in an accident on a ride, has cancelled its plan to reopen on Friday after opposition from police.
On Wednesday night the park announced it planned to open water and animal attractions to raise money for the Red Cross.
But now the site will stay closed until at least Monday.
But the assistant commissioner of Queensland police, Brian Codd, said he was concerned reopening might cause problems for the police investigation.
The area around the Thunder River Rapids ride, which malfunctioned in the incident that killed four people on Tuesday, remains a crime scene.
In a statement on Thursday Dreamworld said: “Dreamworld has been advised by Queensland police services (QPS) that we are unable to proceed with tomorrow’s memorial service as planned. Obviously the integrity of the coronial investigation is of paramount importance and postponing the service will give QPS the time it needs to conduct this investigation.
“We will provide an update to the media on Monday with regard to the memorial service and reopening of the park.”
Earlier Codd told reporters: “We are not going to compromise the speed or thoroughness in order for us to vacate the area and acquire the evidence or facts we need. Let’s be aware of what the implications might be for our ongoing security of the crime scene.”
Police still have a warrant for the park that lasts until next Tuesday and can be extended if required.
Codd said it would be unlikely, but warned the investigation could still shift to other parts of the theme park.
“If there are perhaps other electrical or water or hydraulic sources, or switches from another part of the park that impact on that ride, they form part of the investigation,” he said.
“We’re going through this meticulously, in great depth. The scope of this is quite considerable.”
However, he said any evidence would be protected if the park was reopened to the public.
“Steps have been taken about securing the scene already to maintain the security of that area,” he said.
The premier, Annastacia Palaszczuk, arrived to lay flowers “on behalf of all Queensland families who cannot be at Dreamworld” at the makeshift memorial near the entrance of the park.
On Thursday the mother-in-law of one of the women killed in the Dreamworld tragedy recounted how she died in her son’s arms with their daughter looking on.
Gillian Turner said her son, David Goodchild, reached his childhood sweetheart Kate immediately after the deadly malfunction on the Thunder River Rapids ride on Tuesday which killed four people.
“My son managed to reach his partner ... who died in his arms while his 12-year-old daughter looked on screaming in the background,” Turner said in a statement to reporters in Canberra.
“I would like to believe that my 12-year-old granddaughter was saved so she could tell her little sister what a wonderful mum Kate was.”