About 1500 government linked health laboratory workers were expected to strike over a wage dispute, the National Education, Health and Allied Workers' Union (Nehawu) said.
"We were still mobilising numbers at the start of the strike yesterday [Monday], but... about 80 percent of our members will strike today," spokesman Sizwe Pamla said.
"We have members picketing outside their respective laboratories... but have heard nothing from the employer. We are looking for the [health] department to come on board."
A notice of intention to strike was served on the National Health Laboratory Service (NHLS) on Thursday, following failed wage negotiations. Negotiations had been ongoing since April.
Nehawu wanted a 9.5 percent increase and R2300 monthly medical aid benefit, to be backdated to May 1.
The NHLS, an independent agent contracted to the health department, had offered a 6.5 percent increase and R2100 for medical aid.
The strikers include lab analysts and support staff. Operations at public hospitals nationwide could be affected by a delay in pathology reports and diagnostic tests.
Just R20 for the first month. Support independent journalism by subscribing to our digital news package. 
