Heath visitors in Lincolnshire began a month long strike over pay and conditions on Monday, in a move which county council officials said was “disappointing”.
Unite Union confirmed that workers walked out in a demonstration which will last until December 13.
Workers are taking action over pay and “future job roles” after being transferred from the NHS in 2017.
Unite claim a grading policy introduced by Lincolnshire County Council would cost staff £150,000 over the duration of their careers.
It is the latest walkout since workers first demonstrated for six days back in July when campaigners gathered outside council head offices to protest.
County council officials said the walkout was “disappointing” and added that the council had “increased the number of health visitors across the county”.
But, Unite said “cracks were appearing” in the council’s policy on offering different contracts for grade nine and 10 health visitors.
It added that 32 days (around 450 shifts) have been lost since the first bout of strike action.
Steve Syson, regional officer for Unite, said the union will “keep the pressure on” the council over its system.
“We need to keep up the pressure on the authority to achieve the proper grade 10 role for all the health visitors who have the same qualifications,” he said.
“Tomorrow Unite and the county council are due to meet under the auspices of the conciliation service Acas to see if we are able to move things forward and finally resolve this dispute for the benefit of the families in Lincolnshire and our members.
“The situation is serious as the council is haemorrhaging health visitors who are leaving for better paid positions elsewhere.”
A total of 67% of union members voted for the month long strike. The union represents 76 of the 126 health visitors employed by the council.
Heather Sandy, interim director of education at the county council, said: “It is disappointing that despite constructive discussions with representatives from Unite, this industrial action is being pursued.
“It is important to highlight that many of these issues are part of a national campaign by Unite which has less relevance in Lincolnshire than elsewhere.
“In Lincolnshire, we have increased the number of health visitors across the county, we have maintained the number of visits families receive from a health visitor and we have increased pay for this workforce in line and above the NHS.
“The council’s career progression scheme, which opened in October, means no staff member has to remain on a static salary – all can move on in their careers and be financially rewarded beyond that available in the NHS.
“Unite’s suggestion that all health visitors should have a starting salary £3,500 above their colleagues in the health service is financially unsustainable and would have serious implications for bordering NHS service recruitment.
“Whilst some health visitors have voted to strike, we expect a large proportion of our health visiting staff will continue to deliver safe and effective support to families and their children, as they have since joining Lincolnshire County Council.”