Employees of the 10111 emergency call centre are slowly starting to gather at the Pretoria Art Museum ahead of their march to the Union Buildings.
The march is expected to commence at 12pm where they will hand over a memorandum outlining their demands.
The workers are demanding salary upgrades to be at the same level as other call centre workers at the department of home affairs, SA Social Security Agency, SA Revenue Services (Sars) and the presidential hotline, among others.
The salary upgrades were recommended in 2013 by a task team set up by former police commissioner Riah Phiyega.
About 500 employees are expected to take part in the march which will be led by South African Police Union (SAPU) deputy president Tumelo Mogodiseng.
The strike has been on since 18 July this year.