The union and its doctors last went on strike in 2016 in the lead-up to successfully securing better working conditions as part of a "safer hours" campaign, RDA national president Dr Courtney Brown said.
However, in the current round of negotiations, the DHBs had been trying to "claw back" some of the improved conditions the doctors won in 2016, she said.
"It is disappointing and frustrating that we are being forced to strike just to keep our terms and conditions," Dr Brown said.
"The DHBs' position means RMOs could be moved to any hospital in the country as the DHBs see fit. RMOs could be required to work for more than 16 hours in a row, without guarantee of rest or safety."
National DHB spokesman Dr Peter Bramley says DHBs have been trying to negotiate an agreement that enables clinicians and hospital managers to make decisions about work rosters for junior doctors that deliver better care and better training opportunities.
"We concluded a Collective Agreement with Speciality Trainees of New Zealand
(SToNZ) that provides for flexibility in rostering but haven't reached an agreement
with the RDA."
Chief medical and dental officer Dr John Gommans said around the clock care would continue at Hawke's Bay Hospital.
He asked the public to help its Emergency Department out by first contacting their family doctor if the matter was non-urgent.
"If it's not an emergency, contact your family doctor in the first instance, visit a walk-in medical centre or call Healthline for free advice 24/7 on 0800 611 116.
"Patient safety is our priority and essential hospital services including the Emergency Department, Intensive Care Unit, SCBU, acute medical services, dialysis and maternity care are available," said Gommans.
Just over 24 hours later, Union (APEX) members employed at the HBDHB who are registered pharmacists, pharmacy technicians, pharmacy assistants and trainee pharmacy technicians, covered by this collective, are expected to take strike action from 7.30am on Friday to 7.29am on Saturday.
Community pharmacy services will be operating as usual.
Dr Gommans said contingency planning is in place with pharmacy services similar to that provided during a public holiday period will be in place during the 24-hour strike period.
"A very small number of people collect repeat prescriptions from our hospital pharmacy. However, these people are being contacted directly if they are due a repeat prescription on this day to arrange collection in advance," he said.
"If anyone is unsure whether this affects them, they can call the hospital switchboard on (06) 878 8109 and ask to be put through to pharmacy."
Mediation is planned for Wednesday.
