Queensland police say Dreamworld is still a crime scene and there is no fixed determination when it will reopen.
Assistant Commissioner Brian Codd says the law means police can secure entry to the area if their examinations need to continue. He told local media police "won't comprise speed for thoroughness".
He told local media police are in talks with Dreamworld about the implications of reopening after the event, which "struck a deep emotional chord with people".
The theme park's operating board said after the fundraiser on Friday, the park would open for normal business on Saturday.
"Please let the police do their job," Queensland's Premier Annastacia Palaszczuk said.
"The issue of Dreamworld reopening tomorrow is a matter between the organisation and police... It is up to those parties to make that decision."
Earlier on Thursday she said investigators should "leave no stone unturned" and should be allowed to keep working at the scene without interruption.
"We need public confidence back in our tourist theme parks that things will operate the way they are supposed to operate," she told local media.