A quick-thinking man bitten by a highly venomous dugite managed to kill the reptile and present it to doctors, after one of two attacks by deadly snakes near Perth.

The man encountered the dugite while walking at Lancelin, north of Perth, yesterday afternoon.

He killed the snake after it struck him and placed it in a box before taking it to a medical centre with him so doctors could prescribe the right antivenom.

The man is in a stable condition at Joondalup Health Campus.

Meanwhile, a second man was taken to hospital in a critical condition after he was bitten by a venomous brown snake late yesterday near Mandurah, south of the city.

He was taken to the Peel Health Campus in a critical condition, St John Ambulance said, before being transferred to Sir Charles Gairdner Hospital late last night.

A hospital spokesman said the man's condition was now stable.