More than 800 markers have withdrawn from Gauteng's massive exam marking programme this week, mostly for reasons related to Covid-19.

Gauteng Department of Education spokesperson Steve Mabona said reasons ranged from being contacts of people who had contracted the virus to having comorbidities.

Some were simply afraid, while others had to attend to bereavements.

Mabona said training for more than 12 000 markers began on Monday, but Tuesday's roll call revealed that 887 did not report for duty.

"Different reasons were cited," he added, saying most of the reasons for withdrawing were related to Covid-19.

The markers were replaced by other people on a data base prepared ahead of the mammoth marking season.

They will mark about three million exam scripts produced by last year's merged exams, which saw about 230 000 candidates sitting.

Marking started on Wednesday, and Mabona said the department felt it was on track.