Dramatic security footage has been played to a jury, showing the moments before and after a man allegedly stabbed his ex-fiance to death inside a Perth Courthouse.

Paul Gary Turner, 43, is accused of murdering 33-year-old Sarah Marie Thomas after a mediation session at Joondalup Court Complex on December 20, 2016.

It's alleged Mr Turner smuggled a kitchen knife into the meeting with the mother of his two children and a registrar.

It's alleged Mr Turner smuggled a kitchen knife into the meeting with the mother of his two children and a registrar. (Supplied)

The court heard the mother-of-two was stabbed six times in the face, shoulder and neck, with one wound severing her carotid artery. (Supplied)

When he didn't get his way, prosecutors say he stabbed Ms Thomas multiple times, while the court officer turned to leave the room.

Waiting room CCTV shows the registrar bursting out of the door and calling for help.

Mr Turner then emerges and sits on the floor outside, while Ms Thomas bleeds to death.

Prosecutors claim he snuck the weapon into the courthouse either in his shorts pocket or in a hard white file.

Friends and relatives of Ms Thomas gasped and cried as a graphic photo of her injuries was shown to the jury.

When he didn't get his way, prosecutors say he stabbed Ms Thomas multiple times, while the court officer turned to leave the room. (Supplied)

Waiting room CCTV shows the registrar bursting out of the door and calling for help. (Supplied)

Mr Turner then emerges and sits on the floor outside, while Ms Thomas bleeds to death. (Supplied)

The court heard the mother-of-two was stabbed six times in the face, shoulder and neck, with one wound severing her carotid artery.

Prosecutors allege he used his W.E. Fairbairn Commando Combat skills inflict the deadly knife wounds.