The one-day strike begins at out-of-hours GP care clinics from 8am on Thursday.
It is understood that strikes are also planned on December 23 and 27, as well as a 48-hour stoppage from December 29 and a one-day strike on January 2.
INMO industrial relations officer Gráinne Walsh said industrial action being taken by the union and Siptu will cause disruption at one of the busiest times for out-of-hours services.
She said it will also have a knock on impact on other out-of-hours services in the northeast.
The unions represent over 200 workers at CareDoc including nurses, drivers and receptionists.
The INMO and Siptu said in statement that there has been no meaningful engagement with the healthcare company to avert the work stoppage in a dispute over pay.
Pickets will take place in Carlow, Waterford, Wexford, Kilkenny and Tipperary.
The stoppages comes as GP surgeries are already struggling due to a surge in flu cases while patients will rely heavily on out-of-hours services during the Christmas season.
HSE funding to CareDoc has not been paid to employees so industrial action will go ahead this week, next week and over the Christmas period, according to the unions.
Pickets will take place in the following locations tomorrow:
St Dympna’s Hospital, Athy Road, CarlowHSE Community Care, Cork Road, WaterfordPrimary Care Centre, Grogan’s Road, Townparks, WexfordAyrfield Medical Centre, Granges Road, Ayrfield, KilkennyThe County Clinic, Western Road, Clonmel, Co Tipperary
The unions say they want a Workplace Relations Commission pay agreement for so called state-funded “section 39” organisations paid to CareDoc members.
This would mean they would get an 8pc pay rise.
Unions claim the HSE has provided €647,834 to CareDoc for the purpose of paying the increase.
“It is clear that CareDoc have no solution or alternative plan to avert the action,” said Ms Walsh.
“Their hands-off attitude to paying staff what they are owed is now back-firing. It is clear from their public commentary that they seem to be philosophically opposed to using their profits to pay their staff a fair wage.”
She said the workers have no desire to withdraw their services in the middle of winter, but all other avenues have been exhausted.
“We are willing to meet with management and to consider an interim proposal that delivers the funds already provided, along with an agreed mechanism to resolve the outstanding matters,” she said. “However, CareDoc must demonstrate a genuine willingness to engage.”
Siptu health division industrial organiser, Ger McNally, said the unions have been left with no alternative but to engage in the proposed industrial action.
A CareDoc spokesperson said it was calling on INMO and SIPTU unions to suspend the strikes on “humanitarian grounds”.
“This 24-hour industrial action coincides with the busiest time of the year for Caredoc, which plays a vital role in maintaining a frontline health service for thousands of patients.
“The current winter flu epidemic, expected to peak over the Christmas period, is proving particularly virulent this year as hospitals and GP services already struggle to provide adequate cover.
“Caredoc therefore calls on the unions involved to call off the 24 hour one-day strike actions scheduled for both 18 December and Monday 23 December, as such action will only make an already deteriorating situation even worse, and put patients at risk,” the statement from CareDoc said.
“For its part Caredoc, remains committed to intensive engagement with the HSE and to arriving at a fair result that can hopefully restore pay parity between all its staff members and HSE equivalents, as was the case up to 2021.
“Caredoc will continue to make every effort to ensure the minimum possible impact on patients and their families, from the current dispute,” CareDoc said.