Wednesday is the last chance for students to register and test their log-in details before final NCEA results are out.
After that, parts of the Qualifications Authority website won't be available until results are released starting on 15 January. Students also won't be able to view past results or update their passwords until then.
The authority says students wanting to get their results on the internet need to be registered by Wednesday and should make sure that they can log in.
More than 143,000 young people sat 120 NCEA and Scholarship exams.
A glitch during similar tests in advance of the results in 2013 allowed more than 200 students to get an early glimpse of their scores, sparking a flurry of inquiries and complaints from pupils.
The Qualifications Authority says it has been routinely testing its software to avoid a repeat of last year's problem.