The New Sydney Police was the law enforcement agency that served the Sappora system, and was centrally located on the planet New Sydney. Their jurisdiction included Sappora VII.
After Miles O'Brien disappeared on New Sydney in 2375, Yanas Tigan called in several favors from them. The bureau had heard of a Starfleet Intelligence operative being on the planet and later found O'Brien being beaten up by several Nausicaans. Lieutenant Fuchida later took him to the Tigan's home on Sappora VII.
After it was revealed that Norvo Tigan was responsible for the murder of Morica Bilby, he was arrested by the bureau, and taken away by Fuchida and his partner. (DS9: "Prodigal Daughter")
In addition to this title, the name "New Sydney Police bureau" was also mentioned in the script.