"Mr Frank is still in the extremely early stages of treatment and is in a state of vulnerability where he is yet to address his offending in detail.
"He requires intensive in-patient treatment which is expected to take several years."
Frank, 56, from Wellington, killed his 58-year-old wife while the pair were on holiday in Taupo at Easter this year.
The pair had been married for 32 years and had a 30-year-old son and 28-year-old daughter.
Frank was diagnosed with bipolar disorder in 1987 and began treatment.
The couple had gone to Taupo as Mrs Frank had told colleagues they needed a weekend away as the relationship had been difficult. Frank had been agitated, had started a new job and had been getting possessive over his wife.
Four days before their weekend away, Frank went to his psychiatrist after feeling "overwhelmed" and his medication was increased.
On Saturday, April 15 about 8am, Frank approached his wife as she sat in bed.
He was armed with a large carving knife. He stabbed her twice in the torso, once in the chest and once under her right underarm.
She suffered stab wounds 13cm and 15cm deep, causing extensive bleeding to one of her lungs.
At 8.25am, Frank rang emergency services and told them he had just stabbed his wife.
When they arrived, Mrs Frank was in a lot of pain and was having difficulty breathing. She told emergency services her husband had stabbed her.
She died while being flown from Taupo to Waikato Hospital and a post-mortem examination concluded she wouldn't have survived her injuries.