Police have seized a large snake from a house in the New South Wales Hunter Valley over fears it may have tried to strangle its owner in his sleep.

The 2.3-metre boa constrictor was taken from Wentworth Avenue at Singleton after police received reports it was being kept at the home.

Police said there had been concerns the snake may have eaten a small dog and attempted to constrict its owner in his sleep.

The snake was deemed by National Parks and Wildlife officers to be a non-native species, and it will be euthanased by a local vet due to the danger it poses to native mammals and household pets, and the risk of spreading disease.

Boa constrictors are found in tropical Central and South America and can grow up to four metres in length.

They primarily live in hollow logs and abandoned mammal burrows.

Investigations are continuing and the owner is expected to be charged with possessing an exotic species without a licence.