GOLD Coast police officers were faced with a "very large amount of blood" when they arrived at the Upper Coomera home of slain couple Renee Carter and Corey Croft, a court has been told.

Former-soldier Christopher Robert Carter, who was previously based at Canungra Army barracks, is accused of the double-murder of his ex-wife Ms Carter and her partner Mr Croft at their Skylark St home on January 20, 2015.

Carter on Monday pleaded not guilty to both charges at the start of his trial by a jury of seven women and five men in the Brisbane Supreme Court.

Ms Carter and Mr Croft's five-year-old son was sleeping in the home at the time of the killings and the court yesterday heard he awoke to the grisly scene the following day.

Forensic police officer sergeant Natalie Gorman, who attended the scene of the alleged murder in 2015, this morning told the court "there was a lot of blood" on the door step of the house.

She said she began her examination of the property one day after the couple were found dead in the home because officers first priority had been to collect DNA from the bodies.

Crown prosecutor Glen Cash QC asked Ms Gorman to detail her first observations when she arrived at the doorstep of the home.

"There was a lot of blood on the ground, blood on the door, blood on the wall ... there was a large amount of blood there," she said.

The jury was then shown a series of bloody photographs of the scene.

Some displayed a child's scooter poised at the front door of the property alongside a 1.5m area of blood stains.

On Monday, Defence barrister David Brustman QC told the court Carter admitted to killing the pair but the defence case is that he did not have the intent required to be criminally liable for murder.

Carter appears in the dock in a dark suit and light blue shirt and tie.

The trial is expected to run until next week.