The latest official figures show there are 144 health visitor vacancies across Scotland, just under one in ten of the 1,448 posts.
This gives a vacancy rates of 9.1 per cent, up by almost half (44 per cent) on the same period the previous year when the 93 vacancies from 1,291 staff gave a rate of 6.3 per cent.
Scottish Conservative public health spokeswoman Annie Wells said: “The SNP made a promise to secure 500 extra health visitors, a commitment we welcomed, but it looks like that is going to fall short.
“For any department to have a vacancy rate of nearly 10 per cent is alarming, and shows the strain workers must be under.
“It follows a pattern across health and other public services of not enough staffing and poor workforce planning.
“Health visitors are crucial for a range of needs in our society, it’s not something we can afford to scrimp on.
“The SNP should come clean about progress on this target, and explain how it’s going to secure the additional 500 health visitors it promised.”
The latest vacancy rate, of which 62 have been empty for more than three months, is the highest since figures were first reported this way in March 2015. The Scottish Government announced a £40 million investment plan in June 2014 to create 500 extra health visitor jobs in the next four years. But there have been concerns about staff retiring or leaving the profession.
The Conservatives have said the current workforce trends suggest the SNP is not likely to hit that target but Health Secretary Shona Robison continues to maintain it is “on track”.
Official statistics show there were between 1,047.9 full time equivalent (FTE) and 1,114.7 FTE health visitors in March 2014, from when the pledge was measured. The latest figure of 1,448 in December 2017, published last month, means the extra 500 workers is short by between 100 and 166.
Ms Robison said: “We are providing funding to health boards to achieve an unprecedented 50 per cent increase in the health visiting workforce and we are on track to deliver 500 health visitor posts by the end of 2018, with over 480 students having completed training and 287 actively in training to December 2017.
“We are working closely with health boards to monitor progress, and health boards are accounting for retirals and leavers as part of that process.”