An Auckland woman who survived a suicide pact with her partner has been sentenced to intensive supervision.

Karen Robson, 47, pleaded guilty to entering but surviving a suicide pact after her partner Glenn Bernard Paterson, 45, died in September last year of carbon monoxide poisoning.

Section 180 of the Crimes Act says where two or more people enter into a suicide pact, and one or more of them kills themself, the survivor is guilty of being a party to a death under a suicide pact and is liable to a maximum of five years imprisonment.

Robson is thought to be only the second person convicted under the provision.

The High Court at Auckland was told this morning that Robson and Paterson were drug users who were both on the methadone programme.

Paterson was in a wheelchair following a motorcycle accident and he suffered chronic pain and insomnia.

They decided to kill themselves in September 2011.

They wrote entries in a diary and both signed them.

Justice Raynor Asher said the statements "show a keen sense of commitment to each other and the sadness of your existence at the time".

They attempted suicide on September 9, but did not succeed.

They tried again the next morning and Robson survived but Paterson died in hospital the next day.

Robson told police "everything had become too much" and they were at rock bottom".

Defence lawyer David Niven said Paterson and Robson took steps to ensure they were both responsible for their suicides by leaving both their fingerprints on implements and co-signing the notes.

"They didn't want the situation where one person survived and was charged with manslaughter."

Paterson's mother read a victim impact statement to the court in which she said she had known Robson for five years.

Her son was delighted to meet a woman who would give him "comfort and happiness", she said.

Mrs Paterson said Glenn was happy and excited about getting married, but then, suddenly, everything changed.

"The wedding was postponed. I watched my son getting depressed."

Robson often told her she would be "better off dead".

Mrs Paterson said she saw Paterson and Robson a few days before the suicide and they seemed "happy and content".

The call from the hospital was "devastating".

"Why was my son lying there so lifeless? Yes, he had been feeling depressed, but I know my son and this is not the path he would have chosen for himself."

Mrs Paterson said she only had one question for Robson: "Why?"

"I believed her when she said she loved Glenn and said she wanted to give him the life he deserved."

After Paterson's death she was bailed to a drug rehabilitation facility which she was kicked out of for continuing to use drugs.

She then spent two months in prison before being bailed to New Plymouth.

Reed said the Crown accepted a non-custodial sentence would be appropriate as the emphasis would be on rehabilitation and reintegration.

She said Robson had a history of drug and dishonesty offending and her pre-sentence report said she had a high risk of re-offending by self-harm.

Niven pointed out that the purpose of any sentence could not be to deter others as, by definition, anyone who attempted the crime would not expect to survive and face a sentence.

Justice Asher said the "moral wrongness" of the crime was what Parliament intended to convey and that acted as a deterrence to the public.

He accepted that Robson was "more than remorseful" and was in fact "distressed and fragile".

He sentenced her to two years intensive supervision with special conditions of not using drugs and undertaking rehabilitation and counselling.

"The only way anything remotely positive can come out of this tragedy is if you obey the conditions and reform yourself," the judge said.

- © Fairfax NZ News