About a dozen Hawke's Bay Hospital midwives, who are members of the Midwifery Employee Representation and Advisory Service union (MERAS), will be taking part in strike action on Wednesday.
The eight-hour strike will take place from 11am until 7pm, after pay equity negotiations failed.
It does not affect Lead Maternity Carers (LMCs), chief nursing and midwifery officer for Hawke's Bay Hospital, Chris McKenna said.
She said women preparing for childbirth should not delay seeking care and should come to the hospital as normal.
AdvertisementAdvertise with NZME.
"If you go into labour during the strike, follow your normal birth plan and let your Lead Maternity Carer (LMC) know as you will have already planned."
The safety and wellbeing of mothers and babies were the DHB's top priority, she said, adding a Life Preserving Service agreement had been agreed with the union.
Some services had been deferred, such as elective caesarean sections and non-urgent antenatal or day assessment appointments.
"The main advice for pregnant women and whānau is that if you need to come to hospital, it is safe to do so and you will receive the care you need."
Patients directly affected by the strike have been contacted by the DHB to reschedule their appointments.
McKenna said if a patient's LMC was the DHB community team, they should call (06) 878-8109 and dial extension 6096 for Hastings or (06) 838-9701 for Wairoa.
If their LMC can't be reached they should phone 0800-767-127.