An accomplice in a gruesome double murder has detailed how a woman masterminded the luring, detention, suffocation and strangling of a NSW married couple and then incinerated their bodies to ensure none of the murderers' DNA could be found.

Kim Leanne Snibson, 37, pleaded guilty to the murders of Kathryn McKay and Gregory Hosa midway through her NSW Supreme Court trial in May.

The bodies of Mr Hosa, 56, and Ms McKay, 44, were found burning in metal drums in the Tomerong State Forest, south of Nowra, in January 2006.

Before police were even aware the horse stud couple were missing, Snibson's co-accused Stacey Mark Lea-Caton had come forward to confess.

Lea-Caton, 29, was sentenced in November last year to a minimum prison sentence of 16.5 years and a maximum of 22 years for his part in the kidnappings and murders.

With his head shaved and wearing prison greens, Lea-Caton today gave evidence at Snibson's sentencing in the Supreme Court.

A tearful Snibson looked anxious during much of Lea-Caton's evidence as he recounted how she had directed him and a second man, Andrew Wayne Flentjar, how to deal with the couple and their belongings.

The sentencing of Snibson continues before Justice Terence Buddin.