NSW Police are appealing for public assistance to locate missing teenager Caiden Gardner from the South Coast.

Caiden, aged 16, was last seen on a train between Kiama and Bomaderry about 3pm on Saturday 15 July.

When he did not return home and could not be contacted, officers attached to South Coast Police District were notified and commenced inquiries to locate him. Police and family hold serious concerns for his welfare.

Caiden is described as being of Caucasian appearance, about 175cm tall, of thin build, with shoulder length dark hair styled in a mullet. He was last seen wearing black track pants, a black hoodie, black Nike runners, a black cap and Fluro green jacket.

Caiden is known to frequent the Ulladulla and Mollymook areas and may have travelled to St Peters in Sydney.

Anyone who sees Caiden is urged to contact or Crime Stoppers on 1800 333 000.