King cobra delivers lethal shot

Australia's biggest venomous snake has produced a huge lethal "shot" for reptile wranglers on the NSW Central Coast.

In an enormous yield, four-metre long king cobra Raja has delivered almost 500 milligrams of deadly toxin for veteran handler Billy Collett at Gosford's Australian Reptile Park - enough to fill a shot glass and 40 times the amount of venom of a brown snake.

"It can kill a full grown elephant," Mr Collett said of the eight kilogram cobra.

"It's a very dangerous yield, and they only give you about a third of what they've got.

"They've been known to hold on for minutes when they bite the first time."

Its venom will be distributed between research institutes across the country.

Mr Collett has been milking snakes for almost 10 years but has never extracted venom from a king cobra.

"I was very excited but I was very nervous," he said after the rare extraction on Thursday.

"He's about as thick as my legs."

The milking meant Mr Collett could safely measure and weigh the snake, who was last assessed four years ago.