A British nurse who weighed 134kg has been refused New Zealand residency because of her morbid obesity, despite the need for skilled nursing staff.

The 51-year-old, who was offered a job in a home and hospital for the elderly in a provincial city, met the qualifications for immigration under the skilled migrant category.

But her body mass index of 55.2 was considered unacceptable by the immigration service who declined her application, despite nursing being on a long-term skill shortage list.

Now the Residence Review Board has dismissed her appeal.

For a New Zealand European, a BMI score of 25 is considered overweight, 30 obese and 40 morbidly obese.

The woman, whose waist measured 131cm, wanted to emigrate with her crane driver husband and daughter, who has a degree, after holidaying in New Zealand in 2007.

Medical assessors said that the woman would probably cost the country $25,000 over four years in health treatment.

She argued that she was physically fit, there was no history of cancer or chronic diseases in her family, and her weight did not stop her working more than 60 hours a week.

A medical assessor said that apart from her morbid obesity, she was an otherwise "well lady" and could be reconsidered for immigration if she reduced her BMI to under 40.

The appeal board said that the woman scored relatively highly in the skilled migrant category.

It concluded: "While the appellant is currently healthy, the severity of her obesity meant that two medical assessors found her to be of too great a potential risk to the New Zealand health system to determine that she had an acceptable standard of health."

Though the family would make a "sound" contribution to New Zealand, that did not weigh sufficiently for the board to decide that there were special circumstances in this case.