This home-made gun was taken into a police station, police say.

This home-made gun was taken into a police station, police say.

A man who walked into a Sydney police station was searched and found to be carrying a home-made gun and a silencer, police say.

The 36-year-old will face court next week on charges including possessing an unauthorised pistol after he was arrested at Day Street Police Station in the CBD on Wednesday.

Police said the man walked into the police station's foyer about 5pm to speak to officers. He was wanted for questioning over an alleged fraud offence, relating the forgery of a prescription.

The man was arrested over the alleged forgery, but when officers searched the man they allegedly found the home-made pistol with a silencer and four bullets.

Police said the man also was carrying a 20-centimetre long pocket knife and one gram of the illegal drug methamphetamine, commonly known as ice. 

He was charged with possessing an unauthorised pistol, possessing or using a prohibited weapon without a permit, having custody of a knife in a public place, possessing ammunition, possessing a prohibited drug, and forging or altering a prescription.

The man appeared in Central Local Court on Thursday and has been remanded to reappear on May 15.