The man accused of murdering New Zealand student Emily Longley and his parents were secretly recorded discussing how to cover up the murder, a British court has heard.

Elliot Turner, 20, is accused of strangling his then girlfriend Emily, an aspiring model, last year at his parents' home in Dorset, England.

His trial is under way at the Winchester Crown Court.

His mother, Anita Turner, 51, and father Leigh Turner, 54, both face charges of perverting the cause of justice.

Recordings taken by police after they bugged the Turners' home following Emily's murder were played in court on Friday local time, the Bournemouth Echo reports.

Turner told his mother British police had records showing she had called her husband 40 minutes before calling an ambulance "and that looks guilty".

"But to get out of that would be completely believable," he said.

"What we'll do, like, we'll write this down for y'know what you're gonna say."

Turner was also heard saying a letter needed to be destroyed and saying "dad was all in control of letters".

In another recording, Anita Turner says: "I didn't say that" and her son replies: "No you wanna say something like that".

The court earlier heard recordings in which Turner told his parents he "went absolutely nuts" on the night he is accused of murdering Emily.

Emily had been born in Britain but her family had emigrated to New Zealand when she was nine. She had returned to live with her grandparents in Bournemouth while studying at college when she died.

The trial continues.