The inquest into Mr Guy's 2010 death was put on hold when his brother-in-law Ewen Macdonald stood trial and was ultimately acquitted for his murder.
Coroner Carla na Nagara released her decision today in which she outlined why she would not resume the inquiry.
She said doing so would "only be to pursue a finding that Mr Macdonald - acquitted of Mr Guy's murder - was the killer".
"Having reviewed the High Court trial transcript and the scope of the police investigation I consider the circumstances of Mr Guy's death were adequately established in the course of the criminal investigation and the trial," she said.
Coroner Nagara said she had conveyed this provisional view to Mr Guy's parents and to his widow, Kylee Guy, earlier this year.
Mr Guy's parents accepted this view and took no issue with the coronial inquiry not being resumed.
Kylee Guy, however, sought through her solicitor Chris Morris to resume the inquiry.
Mr Morris submitted to the coroner that the circumstances of Mr Guy's death had not been established and "the identity of the killer is a question of fact directly relevant to the circumstances of the death that has not been determined in the criminal proceeding".
He said Macdonald's acquittal did not render it inappropriate for the coroner to establish who inflicted the wounds to Mr Guy.
"The question of who factually killed Mr Guy is quite a different question to that of whether Mr Macdonald bears any legal responsibility for his death," he said.
Macdonald is currently in jail for serious criminal offences against the Guys and others, including arson.
Mr Morris said the only information about Macdonald's whereabouts at the time of the killing as it stood was contained in police interviews, and a coronial inquiry would be an opportunity for him to be summonsed to give evidence in person.
Mr Morris said it would be in the public interest for there to be a factual finding about who killed Mr Guy, and that Kylee Guy felt strongly - for her and the couple's two sons - that they be assured all available steps had been taken to find out how he died.
Coroner Nagara, however, said that because the killer's identity had not been established, it did not mean the circumstances of death had not been adequately established.
"It is the identity of the deceased that needs to be established. It is not a requirement that a coroner should necessarily establish the identity of other person(s) involved in the death," she said.
Resuming the inquiry would risk the Coroner's Court becoming a "back-stop jurisdiction for the reconsideration - by a different process, by different rules of evidence and to a lower standard of proof - of criminal matters, which is a function fundamentally and uncomfortably at offs with its primary purpose".
