A High Court jury has found a Christchurch man guilty of murder and kidnapping.

Darryn Rosanowski was charged with murdering his former partner's new boyfriend, Darryn McRobert, and then taking the woman hostage in February.

The Crown said it was a premeditated killing and Rosanowski went to the scene with murder on his mind.

The defence argued that while it is accepted Rosanowski caused McRobert's death, the number of wounds argued against a cool, calm murder. It said the correct verdict would be one of manslaughter.  

Earlier, the judge found that the defence of provocation could not be put to the jury. Under law, a culpable homicide that would otherwise be murder can be reduced to manslaughter if the person who caused it did so under provocation.

Justice Fogarty told the jury he had found no evidence of conduct amounting to provocation which would cause an ordinary person to lose the power of self control.     

Rosanowski has been remanded in custody for sentencing on the kidnapping charge in February. Fogarty said Rosanowski would be given a life sentence on the murder charge, and the question of the minimum period of imprisonment would be dealt with on the same date.