New South Wales police have launched a state-wide manhunt for a senior civilian employee accused of stealing firearms.

Sydney Police Headquarters armourer Alan James Cumberland, 38, is wanted for questioning after a raid on his Tuggerah Lakes home on Thursday.

Officers from the Firearms and Organised Crime Squad uncovered "large numbers" of weapons as well as firearms parts, ammunition of various calibres, machining equipment and prohibited weapons.

"He's been misappropriating weapons and weapons parts from the facility," a police spokesperson said on Friday.

Police say Mr Cumberland was alerted to the raid just before it took place and has spoken to his wife since.

Attempts by detectives to contact and locate Mr Cumberland have been unsuccessful, prompting police to launch an appeal for information of his whereabouts.

Police believe he may be armed as a registered rifle and rifle receiver remain unaccounted for.

Organised Crime Squad Commander Ken Finch says Mr Cumberland's name recently emerged in an investigation of criminal use of guns.

"I'm not suggesting that he has specifically supplied weapons to criminals, but that is part of our investigation that is ongoing and we will need to make a number os inquires in regard to that," he said.

The search of Mr Cumberland's home was one of four conducted as part of investigation into organised crime.

A machine gun, ammunition and cash were seized at a property at Bonnells Bay, and a silencer was located at a property at Lalor Park.

Two men have already been charged in relation to those seizures.

ABC/AAP