The NCEA and scholarship exam season starts on Monday, involving almost 140,000 secondary school students at more than 400 exam centres.
New Zealand Qualifications Authority's deputy chief executive Bali Haque yesterday asked students to use traditional English, not text language.
But he said answers using words with missing vowels - in the style made popular through text messaging - would not necessarily fail.
"The litmus test will be ... have they understood the concept of the idea?" said Mr Haque.
"That's what it has always been and that's what it will, no doubt always continue to be."
He said students were expected to use "good, solid, traditional English".
"Please do not use text language."
Rules for the exams include a ban on mobile phones and pagers in the exam room.
Students also can't take blank paper, correcting fluid, books or notes in written or electronic form.
And they can't write or draw anything on their exam paper which may be regarded as offensive.
The exams run from Monday until December 5.
Already 550,000 sets of exam booklets have been printed to send to exam centres.
Once completed, the papers will be sent to almost 2000 markers then returned to students.
"This is the only country in the world in which the papers are sent back to the students after the examination process," said Mr Haque.
Students can expect their results at the end of January.
* 139,590 school students will sit exams from Monday - up from 135,735 last year.
* 8171 will sit Scholarship exams - a slight rise from 7705 last year.
* 48,000+ students will sit the largest exam, level 1 English, on Thursday next week.