Man stabbed at west Sydney boarding house

A man has sustained multiple stab wounds to his neck and chest during a heated exchange in Sydney's west.

Police say the 42-year-old was stabbed during an altercation with another male resident of a Blacktown boarding house at about 7.30pm this evening.

The offender fled before police arrived and the 42-year-old man was taken to Westmead Hospital where he is in a serious but stable condition.