An Auckland computer programmer murdered his Thai girlfriend then lived with her decomposing body in the lounge for nearly a month, a court has been told.



Gordon Hieatt, 49, is on trial in the High Court at Auckland for the murder of sex-worker Nuttidar Vaikaew, 48, in April 2009.



Crown prosecutor Rachael Reed said Hieatt told police he had choked her after an argument got out of control.



Reed said Hieatt killed Vaikaew on April 16 but continued living at her Western Springs, Auckland, flat for over three weeks, going about life as normal - taking trips to Wellington, visiting sex workers and going to family gatherings.



The police officers who responded to a call from Vaikaew's landlord on May 12 were greeted by a smell "indescribable and putrid".



Dead flies and maggots littered the floors.



Vaikaew's body was on a double bed in a curtained-off corner of the lounge, covered in blankets with a dressing gown over the head.



A fan was blowing over the bed to try and alleviate the stench, Reed said.



An examination of Hieatt's computer showed he had been on instant chat site MSM with another girlfriend in Thailand during the time his partner of two years lay rotting next to him.



The chat logs showed him saying Vaikaew "had gone and she was never coming back".



He later said Vaikaew had "made him crazy and he had killed her on Friday".



In other conversations he said he had read jokes all day to cheer himself up.



The trail before a jury and Justice Priestley is scheduled for three weeks.