Around 100 cyclists, van drivers and motorcyclists travel plan to stop work for two days next week, according to a union.
The couriers, who deliver to more than 50 NHS and private hospitals in London and the south-east, plan to strike over their pay and conditions.
Workers are outraged that directors of The Doctors Laboratory (TDL) are receiving huge pay rises in the meantime.
Over the past two years, the union Independent Work's Union of Great Britain (IWGB) have challenged couriers' rights.
In 2018, couriers won full employment rights, giving them access to holiday pay, maternity leave and minimum wage.
It followed the TDL arguing its couriers were self-employed with no employment rights beyond basic health and safety and anti-discrimination rules.
The out of court settlement offered hope of job security for workers both within the company and among similar set-ups, such as Uber and Deliveroo.
