More than 40 NSW police officers laid siege to a house in Sydney's west for three hours last night only to discover the house was empty.

Police from the Tactical Operations Unit surrounded the house in Whalan in the outer western suburbs around midnight following reports of shots being fired in the nearby suburb of Kemps Creek.

After a three-hour stand-off, the heavily-armoured tactical officers breached the house to discover no-one was home.

Police deployed an armoured Bearcat vehicle to the scene. (9NEWS)

Police brought their BearCat — the menacing $400,000 bullet-and-blast-proof armoured personnel carrier — to the siege and used a megaphone to try and persuade the phantom occupant from their dwelling.

The home was later searched by detectives under a warrant after the tactical unit deemed it safe to enter.

Officers and vehicles locked down the streets surrounding the house. (9NEWS)

The large-scale-but-fruitless operation was spurred by reports of an alleged shooting around 2.30pm yesterday afternoon.

Police were acting on reports that a car pulled into the driveway of a Kemps Creek home where a man got out and fired several shots at the 50-year-old resident who was in the yard, the Daily Telegraph reports.

Police were not notified until several hours later.

The man was not injured, but he and the alleged shooter are known to each other and investigations are continuing.