Two arrests after Sydney police operation

A man and woman have been arrested in a police operation in Sydney's west.

Police say they tried to speak to the man, who was allegedly armed with a knife, in the garage of a house on Marana Street, Blacktown on Monday afternoon.

The 33-year-old man was also accompanied by a 28-year-old woman, police say.

Officers secured a perimeter around the house and negotiated with the pair until they were arrested after about two hours at 4.45pm.

They are assisting police with their inquiries at Blacktown police station.

Police would not confirm whether they expected to lay charges but said the operation was not terrorism-related.