The nurses' union is worried the lives of newborn babies and mothers would be put at risk if a proposal to move maternity services from Whanganui to Palmerston North goes ahead.
New Zealand Nurses Organisation (NZNO) professional nursing advisor Cathy Gilmore said the time it takes to travel between the cities "could mean the difference between life and death in some situations".
"Although the proposal suggests that a 'basic' primary maternity service remain in Whanganui it does not address situations where women need urgent medical care during their labour. There are skilled midwives in Whanganui who can manage this type of situation but that is of no use if they don't have the right technology and equipment at the hospital."
More than 800 women a year use the services every year.
NZNO organiser Donna Ryan said another issue was that Palmerston North Hospital had no extra birthing rooms and only three extra ante-natal beds planned if the changes went ahead.
"Staff will be overworked and under-resourced. It is hard to see how the proposed changes will benefit the people of either area," she said.
"Any city with a population of 65,000 needs specialist maternity and gynaecology services. It is imperative that women can access the health services they need where and when they need them."
Whanganui District Health Board was not immediately available to comment.