A large percentage of yeah nine school students will need extra help in up to three subjects to be eligible to sit their Higher School Certificate (HSC) in three years' time.
Data from the 2017 NAPLAN testing reveals that as much as 70 per cent of this years' cohort will be required to undergo further testing in reading, writing or numeracy.
Under new rules, students that do not achieve at least a NAPLAN band 8 will need to sit an online exam in 2018 in order to qualify for the HSC.
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Almost 70 per cent of year 9 students will sit further testing in reading, writing or numeracy
NSW premier Gladys Berejiklian told The Sydney Morning Herald, 'The results also show the NSW government's introduction of minimum standards have yielded outstanding results with students showing great improvements in literacy and numeracy.
The mixed bag of results for Australia's school children, released on Wednesday, show little improvement from a year ago but the longer-term trend offers some hope.
23 per cent of NSW students, which was 'more than expected' have already qualified to take their HSC in 2020.
The initial NAPLAN literacy and numeracy results from May's tests show over the past decade there has been gradual growth in the number of students performing at the top end, especially in year three reading results.
The Australian Curriculum, Assessment and Reporting Authority says the same trend is evident in other areas, although it is not always enough to lift national averages.
'What the 10-year data indicates is that change is happening...and this is to be welcomed,' chief executive Robert Randall said on Wednesday.
'If this improvement can be replicated across more domains, years and states, then a lift in average results nationally will be seen.'
There has been some growth in the number of students performing well over the past decade
In South Australia, schools will receive a $67.5 million funding increase following the poor results.
The extra funding will be used to employ more teachers to help improve literacy and numeracy, SA Education Minister Susan Close said in a statement on Wednesday.
The minister also noted that the NAPLAN results will be analysed and used to direct extra funding to primary schools.
Extra funding will be given to primary schools in South Australia to lift