A family of four were found dead at a house in Sydney's north on Monday morning in a scene described by police as "extremely confronting".

Officers were called to an address on Sir Thomas Mitchell Drive in Davidson about 11.20am and found the bodies of Fernando Manrique, 44, his wife Maria Claudia Lutz, 43, and their two children - Martin, 10, and Elisa, 11, inside.

Police also found a dead dog at the house.

Neighbours said the family, originally from Colombia, had lived in the house for about 10 years.