Police are appealing for the public's help to find the owner of a silver ingot found at a beach near Coffs Harbour six months ago.

The large chunk of precious metal was found at 5pm on Sunday July 31 at Mylestom Beach, 25 kilometres south of Coffs Harbour.

The person who found the ingot handed it in to police, but after nearly six months of searching they are yet to locate the owner.

"It's just a very unusual piece of property to be handed into police," Inspector Brett Henderson-Smith, from the Coffs-Clarence Police District, said.

Police said the ingot was stamped with a serial number and had other identifiable markings.

Anyone who comes forward to claim the bar will have to provide specific evidence or a certificate of authenticity.

Mr Henderson-Smith said few details had been released due to the unique nature of the item. 

"It's such an unusual item that the rightful owner of the lost property would be aware of the unusual nature of it," he said.

Police photos released to the public show the bar to be slightly larger than a 30-centimetre-long ruler.

The bar's value has not been calculated, but is estimated to be substantial.

"Probably a significant amount of money in our view," Mr Henderson-Smith said.

Silver is currently worth more than $1,100 a kilogram.

Anyone with information should contact Coffs Harbour police station on (02) 6691 0799 or Crime Stoppers on 1800 333 000.