The phrase "authorities originally" is correct and usable in written English.
It can be used when discussing the initial stance or actions taken by authorities in a particular context or situation.
Example: "The authorities originally planned to implement the new regulations by the end of the year."
Alternatives: "the authorities at first" or "the authorities initially".
The authorities originally suspected Iraqi agents, but they ultimately traced the attack to two California teenagers.
The authorities originally said that only about half that number wanted to go home.
The 2010 spill could have been worse if it had reached Lake Michigan, as authorities originally feared it might.
The authorities originally identified the boy as Kymell Oram when he was first brought to the hospital.
The authorities originally planned to stab him to death, using the identical method he had used during his crime.
Are you trying to suggest that the authorities originally in question have won the struggle for cultural and political power?
The transportation authority originally presented the images during a July 25 committee meeting at which it revealed details like the security plan for crowd control during new releases.
The state authority originally envisioned financing the arena renovation with a loan to the Kushner-Corzine group, if it buys the team.
The authority originally chastised Silverite for "serious and material contract breaches" on the earlier project because of a major violation of asbestos procedures in the Queens-Midtown Tunnel.
It is in this area that many residents protested that the overhead line the authority originally planned for a four-mile stretch in Water Mill and Bridgehampton would be a visual blight and, in a hurricane evacuation, a hazard.
The authority originally set a minimum price of 150 million Singapore dollars ($87 million), to be paid upfront, a price some analysts had said was too high considering Singapore's small population.
