A 23-year-old quietly drank himself to death after sneaking into a screening of Twilight: Eclipse in Wellington.

Damian Anthony Smythe's death was "a sad and tragic loss of life of a person so young", Wellington coroner Ian Smith said.

Mr Smythe was described in the coroner's report as an unemployed man with no fixed abode.

CCTV footage of Mr Smythe showed on July 4 2010 he snuck in to a 6pm screening of the vampire movie at Reading Cinema on Courtenay Place without paying for a ticket. He was alone at the time.

A woman who sat behind Mr Smythe said she had seen him drink at least half a bottle of Johnny Walker Red Label whiskey straight before slumping forward in his seat and snoring.

About five minutes before the movie ended, he fell silent.

He was found by cleaners who thought he was drunk and asleep, but was cold and blue in the face.

He had an empty one-litre bottle of whiskey beside him.

Ambulance staff were called and police alerted after it was clear Mr Smythe was dead.

Police records showed Mr Smythe was a transient person and was known to be an alcoholic with a police record of stealing from businesses and trespass.

Mr Smythe came from a split home and had very little contact with his mother. His father had reportedly tried to get help for Mr Smythe’s alcohol addiction but he had not gone through with the rehabilitation.

Mr Smith said an autopsy confirmed the cause of death was alcohol poisoning.

Toxicology reports revealed no evidence of drugs but found a blood alcohol level of 569 milligrams per 100 millilitres of blood.

"It would appear that the deceased has, to some degree, fallen through the cracks and that he appears to only have received limited support, partly brought about by his itinerant nature of his life," Mr Smith said.