"Kids have burst into tears, the vast majority of students, as many as 60 per cent, have experienced network disruptions," said the teacher, who did not want to be named. Loading "It'll drop out for as long as 30 seconds, it's happening multiple times for some students and the timer doesn't stop, it's not a sound testing condition at all." Wenona School’s principal Briony Scott said of the 368 tests submitted by her students on Tuesday, 341 experienced at least one disruption. “93 per cent of students had at least one disruption,” Ms Scott wrote on Twitter. Other students were unable to log on, lost their work during dropouts or were told to re-sit the writing test a day later, giving them time to consider responses, according to the Australian Education Union.

"Following the chaos of the widespread NAPLAN online IT outages yesterday, no one can have any faith in the data which is produced by this round of testing," AEU president Correna Haythorpe said. "There was widespread concern about the validity and comparability of test data last year and now we've seen an IT collapse broadly across the country, we're very concerned about what this means for a reliable, valid and consistent assessment of student achievement." However, experts say the move to online is necessary to improve the tests and allow results to be made available to schools faster. Jim Tognolini, the director of the University of Sydney's educational measurement and assessment hub, said adjustments can be made to make comparisons between online and paper tests valid and that disruptions during the transition to online are "worth it for a test that isn't high stakes". "Teachers can get results back basically instantaneously, which is much more useful for helping kids improve," Professor Tognolini said.

Minister Mitchell said: "It is obviously very disappointing that staff and students were inconvenienced in this way. ACARA needs to be liaising closely with affected schools to ensure there is support for these tests to be completed." Loading About 50 per cent of schools are doing NAPLAN online and all schools are expected to go digital next year, but the Sydney teacher said the timeframe was "entirely unrealistic". ACARA is investigating the problems and has apologised to schools for "any inconvenience". "If technical issues are experienced in the coming days, there are procedures in place to manage them and ensure that all students are able to take the tests. This includes taking the test on paper as a last resort," a statement by ACARA read on Wednesday.

"The technology and logistics of a national online project of this size are highly complex, involving national testing authorities, states and territories and schools, and the cooperation and assistance of all involved in appreciated." A spokesman for the NSW Education Standards Authority, which administers NAPLAN in NSW, said "schools experiencing disruptions are being asked to pause the test session and contact NESA". "NESA is continuing to work with the national authorities, ACARA and Education Services Australia, to better understand the issues and find solutions," the spokesman said. "NESA has received feedback from schools today that testing is going more smoothly than yesterday and we are monitoring this closely." While NSW schools began transitioning to the online platform last year and some Sydney teachers said they have been trained in getting students back online and keep tests running "smoothly", other states are considering pulling out of the online system.