A mother in New Zealand has been found guilty of killing her two children and hiding their bodies in suitcases, in a high-profile case that shocked the country.

Hakyung Lee, 44, was convicted of murder at the Auckland High Court on Tuesday, after a trial that lasted about two weeks. She had pleaded not guilty.

Lee's lawyers argued that she was insane at the time of the killing, which happened months after her husband died of cancer. But prosecutors argued that her actions were calculated.

The remains of her children were discovered in 2022 by a family who had purchased the contents of an abandoned storage unit at an auction in Auckland.

The bodies were believed to have been stored there for several years.

Lee was arrested in Ulsan, South Korea, in September 2022 and extradited to New Zealand later that year.

During the trial, the court heard that the children's bodies had no sign of trauma, though it was clear they had been killed by someone.

A pathologist found they had died by homicide by unspecified means, including the use of Nortriptyline, an antidepressant, the prosecution said.

The court heard that Lee picked up her prescription for the drug from a pharmacy in August 2017 – five months after her husband, Ian Jo, was diagnosed with cancer.

The defence claimed Lee's mental health deteriorated after her husband's death and came to believe it was best if they all died together.

This led her to try to kill herself and her children with the antidepressant, but she got the dose wrong – when she woke up, her children were dead. While she did kill her children, she was "not guilty of murder by reason of insanity," her lawyer said.

But the prosecution argued that Lee had demonstrated rational thought by hiding the children's remains, changing her name and moving back to South Korea, the prosecution said.

The killings were a "selfish act to free herself from the burden of parenting alone", the prosecution said.

On Tuesday, Lee had her head down and gave no reaction when the jury delivered the verdict, which came after around three hours of deliberation.

Lee is set to be sentenced in November. She faces a maximum sentence of life in prison, AFP reported. (BBC)

• PHOTO: An Auckland court has rejected the defence’s argument that Hakyung Lee was insane at the time of the killings. Photo courtesy of TVNZ.