Police have launched an appeal for information to locate a 14-year-old girl reported missing from the Central Coast of New South Wales.

NSW Police said Sophia Nicolussi, aged 14, was last seen at a hospital in Gosford on September 17. Police were notified after she was unable to be located or contacted, with officers from the Brisbane Water Police District commencing inquiries into her whereabouts.

Police said Sophia was last spoken to on Wednesday, September 30, before the latest search efforts began. Because of her age, police and her family have expressed serious concerns for her welfare.

Sophia is described by police as approximately 155 centimetres tall with a thin build, black shoulder-length hair and hazel eyes. Police have also provided a physical description to assist members of the public who may have seen her.

Investigators believe she may frequent areas around Brisbane Water, Morisset and the wider Central Coast. Police are asking residents, commuters and anyone who may have recently travelled through those areas to consider whether they have information that could help locate her.

The appeal comes as officers continue inquiries into her movements and attempt to establish where she may currently be.

Police have asked anyone with information about Sophia's whereabouts to contact Gosford Police Station or Crime Stoppers. Information provided to Crime Stoppers is managed confidentially.

Authorities have specifically asked members of the public not to post information through NSW Police social-media pages. Instead, information should be passed directly to police or Crime Stoppers so investigators can assess it appropriately.

The Central Coast has a large network of residential areas, public transport routes and surrounding communities, making public assistance potentially important in establishing a missing person's movements.

Police have not provided information suggesting what may have happened to Sophia, and the investigation remains focused on locating her and ensuring her safety.

Anyone who believes they may have seen her or has information about her whereabouts is urged to contact police as soon as possible.