A teenager found dead in his bed yesterday morning died from a head injury, police say.

Family members found Waylin Te Rau Aroha Ngarangione, 19, dead at his family home in Manutuke, 13km southwest of Gisborne, about 9am yesterday, Detective Senior Sergeant Craig Scott of Gisborne CIB said.

A post mortem examination completed in Auckland this morning revealed Mr Ngarangione's death was caused by a serious head injury he was believed to have received during an incident at Manutuke last Wednesday night.

A homicide inquiry had been launched as a result.

"The scene is currently being examined by both the police and the forensic scientists and inquiries are continuing as to how the fatal injury occurred," Mr Scott said.

Earlier today, Mr Scott told NZPA Mr Ngarangione's family was "obviously very upset, as you would be when anyone loses a loved one or a family member".