A man considered to be a “significant threat” to the public will face multiple charges after police uncovered a weapons stash at his home in Sydney’s west last week.

Former prison guard Michael Kay, 64, was arrested following the discovery on Tuesday.

Acting on "a red flag warning" from the Australian Border Force, police executed a warrant on his Richmond home about 9am.

A man considered to be a “significant threat” to the public will face multiple charges after a police uncovered a weapons stash at his home in Sydney’s west last week. (NSW Police)

A 64-year-old man has been arrested. (NSW Police)

Michael Kay is a former prison guard. (Facebook)

"The male was taking the garbage out and during his arrest, they located five edge-weapons on his person," State Crime Commander Acting Assistant Commissioner Stuart Smith said today.

"Police were certainly not prepared for what followed."

During the search, officers found five rifles and an assortment of parts and accessories, in addition to 2000 rounds of ammunition.

During the search, officers found five rifles and an assortment of parts and accessories, in addition to 2000 rounds of ammunition. (NSW Police)

The 64-year-old reportedly had his firearms license revoked in 2009 owing to mental health issues. (NSW Police)

Among the weapons stockpiled were armoured helmets, ballistic vests and handcuffs. (NSW Police)

The search also turned up three crossbows, about 100 arrows and more than a 100 knives, swords and tomahawks.

Police also located five pistols and handguns on the property during a visit the following day.

Among the weapons stockpiled were armoured helmets, ballistic vests and handcuffs.

The search also turned up three crossbows, a hundred arrows and more than a hundred knives, swords and tomahawks. (NSW Police)

The 64-year-old was also in possession of sniper training manuals and shirts carrying “doomsday” patches. (NSW Police)

Kay was also in possession of sniper training manuals and shirts carrying “doomsday” patches.

"What was deeply concerning to police during the search is that we recovered almost 2000 rounds of ammunition," Det. Supt Smith said.

"During the search warrant, there was quite a volume of literature located which included terrorism-response information, response to disasters, the history of human kind and a number of books by famous snipers. They contain particular weapons we found during the search."

"What we found was a deeply troubled individual with a history of tactical weapons training. He was dismissed from corrective services.

"This person posed as a significant risk to the community.

"We have no direct information on what this individual intended to do with what we found. He is a deeply disturbed individual.

"The threat was real, significant and imminent."

Kay's Facebook page features a number of images of weapons. (Facebook)

“What we found at the premises was a disturbing individual who had a cache of tactical weapons and 50 times the ammunition required of a sports shooter, and concerning literature." (NSW Police)

Kay has since been arrested and taken to hospital for assessment.

He is expected to face multiple firearms and weapons offences upon release.

Det. Supt Smith said the 64-year-old had his firearms licence revoked in 2009 owing to mental health concerns.