Today matric pupils will write their last exam paper. The 2009 National Senior Certificate examinations started on October 26.
This year almost 582000 pupils sat for the examinations.
On Wednesday pupils wrote Agricultural Science Paper 1 and English Paper 3, and yesterday they wrote Agricultural Science Paper 2, Nautical Science Paper 2 and Tourism.
The Department of Basic Education said there were 12 incidents during the exams, but that these had not affected the exams' integrity.
In Mpumalanga, a week before the exams, a teacher and two pupils were arrested for leaking Maths Paper 1 and 2, Physical Science Paper 1 and 2 and Accounting.
The department said there were "isolated problems" such as that relating to the physical science paper in Gauteng, but that these were being resolved.
Last week the wrong exam paper was dispatched to a Soweto school for a partially sighted student.
A Physical Science Paper II was received for the partially sighted student, instead of Physical Science I, which other students were writing.
The incorrect paper was sealed and returned to the Gauteng distribution centre. An investigation is under way.
Department spokesperson Granville Whittle said: "The national guidelines for marking is that it has to start on December 6. In Gauteng they started two weeks ago and Mpumalanga starts on Wednesday. We are flexible with marking as long as this is completed by December 18."
Whittle said there were 45000 markers at 10500 centres across the country.
Matric results are expected to be released on January 7.