Two-hour strikes planned for Friday, Saturday, Sunday and Monday at Tauranga and Whakatāne hospitals have been called off.
Strikes planned for Tuesday and Wednesday are set to go ahead. The two parties are working to agree how life-preserving services will be provided for those days.
Union co-leader (midwifery) Caroline Conroy said she had withdrawn the strike notices on days for which the union had signed agreements, although she still believed those agreements unfairly called for staffing "way in excess of what would normally be provided".
She said, as well as having four midwives on-site, the health board wanted four midwives available on-call off-site for strike days, when normally there would be none.
The health board's usual "completely inappropriate" practice if more staff were needed was to phone midwives on their days off and ask them to come in, she said.
For Tuesday and Wednesday's strikes, she hoped to negotiate to have fewer people on-call off-site.
Conroy said she was disappointed the health board had decided to get lawyers involved.
Other DHBs had been more willing to co-operate and some had reduced their staffing requirements in respect of midwives' right to strike.
"The DHB must know midwives would never do anything to put the safety of mothers and babies at risk," she said.
Health board chief executive Helen Mason said the organisation respected midwives' right to industrial action.
"At the same time, the board's priority concern and responsibility is to ensure the safety of mothers, babies and staff."
She said the contingency planning was about safety and was based on "knowledge of the operational context of clinical and staffing requirements".
The health board did not specifically address questions about whether the staffing levels it had sought during strikes were higher than during normal shifts.
New Zealand College of Midwives chief executive Karen Guilliland said she was "disappointed" the health board was "demanding more midwives work during the daily two-hour strike periods than would normally be required".
"The whole point of the midwives' strike action is to point out to all of the DHBs that the current staffing ratios are not safe. The Bay of Plenty DHB, by its actions, now seems to be agreeing that they need more midwives than they usually have on duty each shift if safety is to be achieved."