A New Zealander who will stand trial in the US this week accused of the brutal murder of his new bride will try to convince a jury he was suffering a mental disorder, his lawyer says.

Blazej Kot had previously denied slashing the throat of his wife Caroline Coffey in New York State last June.

Prosecutors say the 25-year-old Aucklander left Coffey to die in a park near their Ithaca apartment, exactly a month after their wedding.

But his lawyer, Joseph Joch, said that Kot's "mental disease" would be a significant part of the defence.

Speaking from the US, Joch said: "He is not maintaining his innocence and to say so would be erroneous. Under our system you plead guilty or not guilty. And he has pleaded not guilty [to murder].

"It's going to be a terribly unusual case because of the facts."

Joch said Kot, who is on remand at the Tompkins Country Correctional Facility in New York state, had a psychiatric disorder known as extreme emotional disturbance.

He said Kot's condition would be raised as a mitigating factor, which might reduce the charge to manslaughter.

Joch said Kot was feeling anxious about the trial, but he refused to say whether Kot would take the stand in court.

He confirmed Kot's parents Barbara and Leszek, who live in east Auckland, have travelled to the US for the trial and would testify in Kot's defence. His sister Lucja may also give evidence.

Kot and his sister were studying computer science at the prestigious Cornell University.

Kot was born in Zaire and raised in New Zealand by his Polish parents.

The former University of Auckland student met his future wife at Cornell, and they married in October 2008.

The couple had a second wedding with family in Costa Rica on May 2, 2009.

Coffey was murdered a month later.

Kot was seen driving into Taughannock Falls State Park on the night of the murder. A park police officer approached the car and saw Kot, wearing a bathrobe and covered in blood.

Kot took off and led state troopers on an 8km chase. When officers caught up with him, he had a self-inflicted cut and an "edged weapon".

A jogger found Coffey's body on a trail the next day.

Tompkins County District Attorney Gwen Wilkinson said security would be kept "tight" during the trial.

Kot faces a sentence of 25 years to life in prison if he is found guilty of murder.