Second boy charged over armed hold-up

A second teenager has been charged over an armed robbery at a service station on the NSW central coast.

Police said three teenage boys entered a service station in Wyong on Sunday night and allegedly threatened the attendant at gunpoint before fleeing with cash.

A 16-year-old boy was arrested at a home in Watanobbi on the Central Coast on Wednesday and charged with robbery while armed with a dangerous weapon.

He has been refused bail and is due to appear at a children's court on Thursday.

Police previously arrested a 14-year-old boy at the same home.

On Tuesday, police seized a firearm from a different house in the same suburb.