Ms Daley, 33, died from injuries sustained in the violent sex act with her "'on-again-off-again" boyfriend Adrian Attwater, 42, and Paul Maris, 47, on a 2011 Australia Day camping trip to Ten Mile Beach.

Following a five-week trial at the Coffs Harbour Supreme Court, a jury on Wednesday found Attwater guilty of manslaughter and aggravated sexual assault, and Maris guilty of aggravated sexual assault and hindering the discovery of evidence.

An autopsy found Ms Daley died from blood loss from horrific internal and external injuries after a violent sex act was performed on her. 

Crown prosecutor Philip Strickland SC told the court in his opening address that the two men and Ms Daley "them drank a lot of alcohol on that day".

At dusk, they stopped halfway up the beach in Maris' troop carrier where Attwatter and Daley got on a mattress in the back.

Attwater "repeatedly and vigorously" sexually assaulted Ms Daley for a couple of minutes, Mr Strickland said.

Maris joined in with a sex act at Attwater's invitation, the barrister told the court.

Attwater only stopped the assault when he noticed blood on his hand and Maris later burnt her bra and the bloodstained mattress "because it stank," the Crown said.

Confronting photos shown in court showed injuries to Ms Daley that caused significant blood loss.

The assault "substantially or significantly contributed to her death," Mr Strickland said.

Her autopsy also revealed a small amount of methylamphetamine and a blood alcohol concentration of 0.303 - meaning she was "grossly intoxicated".

The prosecutor said Attwater told police "she was blind, she was off her f---ing face last night".

Attwater claimed Ms Daley had a fit or seizure in the ocean when she went for a swim while naked and he performed CPR after dragging her back to shore.

When questioned about how the trio came to have group sex, Attwater said: "These things happen ... girls will be girls, boys will be boys."

Both men told police they thought it was consensual.

Mr Strickland said Maris told police: "Well she didn't object when I jumped in the back, she'd moved over to give me oral."

Police initially charged Attwater and Maris over Ms Daley's death but, in 2012, the Office of the Director of Public Prosecutions decided not to proceed with the prosecution.

Last year, the DPP, Lloyd Babb, SC, took the rare step of asking an independent legal adviser to review the case, including whether Attwater and Maris should proceed to trial.

That review followed a Four Corners investigation, in which the two men now charged over Ms Daley's death were shown in police videos recorded at the time of Ms Daley's death describing events that took place in the back of Mr Maris' four-wheel-drive.

Ms Daley's family and supporters had been highly critical of the DPP for not prosecuting the two men. 

AAP