The largest exam session of this year's NCEA, Level One English, was held on Tuesday morning.
More than 47,000 candidates are taking the English exam.
The senior school exams began on Saturday, with two Scholarship subjects.
By the time the exam season finishes on 2 December, more than 140,000 students will have sat a total of 1.8 million individual NCEA standards.
The smallest session was Scholarship Latin, held on Monday, with just 25 candidates.
A team of more than 2,000 markers from around the country will assess all the papers by Christmas. Results are scheduled to be sent out in mid-January.