A HUGE cache of weapons and ammunition including 10 guns, dozens of knives and

swords and three crossbows has been found at a home in northwest Sydney.

Police say a 64-year-old man has been arrested and is in hospital for assessment.

The Daily Telegraph identified the man as former prison guard Michael Kay, who was banned from owning a gun nine years ago.

An alarming collection of literature covering topics such as military tactics, counter-terrorism operations and a book featuring interviews with the world’s best snipers were also found in the home where Mr Kay was arrested.

Drugs and Firearms Squad officers said the case was unlikely anything they had come across before and feared Mr Kay may have been planning a mass shooting, The Telegraph reported.

Detectives searched the Richmond home last Tuesday morning after a tip-off from the Australian Border Force about imported firearm parts.

They seized five rifles, including a semiautomatic, more than 2000 rounds of ammunition, some gun parts and accessories, three crossbows with arrows, and more than 100 knives and swords.

The detectives also seized ballistic vests, armoured helmets, handcuffs, documents, literature and a computer.

They later found another five guns, including pistols and handguns, after investigating a report of a suspicious bag hidden in a stairwell at the property.

Police said the resident of the home was expected to be charged with firearms and weapons offences upon his release from hospital.