The Special Investigating Unit (SIU) is probing more than 600 contracts related to the Covid-19 pandemic estimated at more than R5 billion.
Briefing the standing committee on public accounts, SIU officials told MPs that the investigations were found in all spheres of the government.
A report tabled to the virtual meeting, showed that a total of 658 contracts estimated to the tune of R5 083 478 584 were investigated.
These had formed part of the proclamation after the SIU received allegations from the director-general of the Gauteng province, whistle-blowers and anonymous whistle-blowers.
Chief investigating officer Pranesh Maharaj said allegations involved procurement in response to Covid-19 by state institutions.
SIU head Andy Mothibi said they would like to see an effective investigation and also committed to report to President Cyril Ramaphosa during the six-month intervals.
In Gauteng, matters under investigation include 90 companies used to procure PPE, 30 companies used to procure Medical Equipment, and 32 companies for services related to catering, flights, accommodation, counselling sessions of staff, legal costs, car hire, printing, computers and patient care.
There are also five companies for infrastructure projects including the two warehouses to house PPE and one Covid-19 quarantine site.
In the Eastern Cape, the matters relate to irregular procurement of Goods and Services; decontamination, infrastructure, accommodation and PPE and lease of 55 000 tablets and eLearning platform.
The report said the refurbishments and alterations to hospitals and clinics and non-payments of TERS were to be probed.
The SIU is investigating in KwaZulu-Natal irregular procurement of Personal Protective Equipment (PPE) in the Department of Social Development; irregular procurement of blankets for the Covid-19 pandemic and irregular procurement of PPE in the Department of Education.
In the North West the matters under investigation relate to procurement of sanitizers, procurement of dam quarantine side, PPE, abuse of petrol cards for Covid-19 related travel, distribution of food parcels and procurement of Temperature Guns.