The online system for school exams faces a test of its own this morning when thousands of teenagers try to log in to the level 2 English exam.
Teachers told RNZ it was critical there was no repeat of last week's failure when the Qualifications Authority stopped hundreds of students from joining the level 1 English exam because the system was not coping with the volume of log-ins.
That glitch came just a week after a similar problem with an online literacy and numeracy test.
PPTA acting president Chris Abercrombie said the Level 2 English exam would have thousands of participants and it had to go without a hitch.
"It's going to be really huge. It's the second-biggest exam day in our exam time. Level 1 English is the largest and level 2 English is the second-largest.
"So these are massive exams, we're talking well over 15,000 students (across New Zealand)... So it's really important NZQA get this right," he said.
Abercrombie said some students had struggled last week when they were forced to switch from the online exam to a paper exam.
"It's a little bit jarring and can throw some kids," he said.
Secondary Principals Association president Vaughan Couillault said people were a bit nervous in light of the recent problems, but NZQA had assured principals it had worked to ensure they were not repeated.
"We've had a couple of times in the last few weeks where the quantum of people logging on has pushed the digital solution that NZQA has purchased to its limit, and NZQA have been working with their provider to create a solution to that.
"So once bitten twice shy and all that sort of stuff. Everybody, including people at NZQA, I am sure is understandably apprehensive," he said.
"However there are fewer people needing to access digital exams tomorrow than there were last week and the system last week seemed to be able to handle 18,000 concurrent connections and work has been done since then."
Couillault said his students were pretty relaxed when they found they could not log in to last week's English exam, but that would not have been the case for all students.
Otahuhu College principal Neil Watson said the Qualifications Authority had encouraged his school to opt in to online exams, but this month's problems confirmed his reasons for staying out.
He said online exams must be fail-safe before NZQA could expect all schools to go for online assessment.
"The unfortunate disruption this year for both the literacy and numeracy, and also Level 1 English, says there's still a fair bit of work to do on the engineering side to make sure the software can cater for what should have been easily predictable demand.
"We've been reluctant to do it for that reason and also the equity issue around online assessment and that comes down to both the quality of devices being used, the access to WiFi you have at home - all these things impact on a student's ability to access online learning," he said.
Watson said his school's students had attempted the online literacy and numeracy exams earlier this month without problem, but he was worried students might be disadvantaged if they were not familiar with using computers for learning.
He doubted any other countries were moving to a fully digital school assessment system.
NZQA assessment deputy chief executive Jann Marshall said the number of students expected to attempt the digital exam on Wednesday morning was lower than those able to log into the digital exam platform on Friday.
Level 2 English was the second largest digital exam with more than 40,000 students entered, of whom around 22,000 are entered digitally, she said.
"Typically, around 20 percent of students do not attend an exam they are entered for.
"In addition, some students entered digitally decide to complete their exam on paper instead."
Last year, nearly 45,000 out of a total of 140,000 exam candidates sat an online NCEA exam and the Qualifications Authority wants all students to do their exams online by 2026.