However, she has assured the public there would be minimal disruption because adequate cover would be put in place during the rolling strikes.
"We will ensure all mothers and babies receive safe care during this time," she said.
Lyndal MacBride works as a rostered core midwife based at Whangārei Hospital and is on call occasionally, which means she can be called up in the middle of the night maybe once a month or once every two months.
Aside from helping deliver babies, she helps women post operatively after caesarean sections and assists with teaching about breastfeeding.
"We'll take women right through their whole labour, making all of the decisions for their labour, and also referring to a consultant obstetrician if it's required or our midwife colleagues, so we have a really specialist role, quite different to a nurse."
Meras industrial co-leader Jill Ovens said the strike came after an year of negotiations.
Members have rejected the pay offer from the DHBs because it was refusing to recognise midwives' skills and responsibilities by offering them the same pay scale as nurses, Ovens said.
"The union wanted a further percentage to recognise the difference and a retention allowance to address the pressing midwifery shortage."
DHBs spokesman Jim Green said Meras has turned down an offer of 9 per cent pay rise over the next 18 months plus two pay step increases and a lump sum payment.
"That's a very good offer and the same as other midwives employed by DHBs," he said.