CANBERRA, Dec 13 - The preliminary National Assessment Program -- Literacy and Numeracy results in August showed small gains across the board in reading and numeracy since 2008, but results for writing had dropped since 2011.
Now the full NAPLAN report, released on Wednesday, shows their reading skills have also failed to advance.
There has been improvement at primary school levels but stagnation among secondary school students.
The reports shows girls outdoing boys in numeracy and Indigenous students and those from other backgrounds making the most progress.
Minister for Education Simon Birmingham acknowledged there had not been any real progress among secondary students.
"While there have been pockets of improvement, we're not seeing the sort of consistency we should expect in these results," he told The Australian.
"We know how vital literacy skills are to setting students up for life beyond school, so the ... flatlining of reading results should act as a wake-up call that some changes are required."
"This is a worry. We see at best stagnating results," Birmingham told the Nine Network on Wednesday.
"The results overall are not what you would expect for a system which is seeing record and growing sums of funding invested into it."
A separate release of testing of civics and citizenship shows Year 6 performance remained stable in 2016 but Year 10 outcomes have fallen.
More than 50 per cent of Year 6 students achieved at or above the proficient standard, compared to 38 per cent for Year 10 students.
The civics and citizenship test measures understanding and knowledge of Australia's systems of government and issues of identity and culture.
"These results are woeful and should be of serious concern," Birmingham said.
AEU Federal President Correna Haythorpe said the results showed that Australia’s overall performance on the NAPLAN test had plateaued while critical gaps in student achievement remained.
“These results highlight the deep inequity in our school funding system. Students from low socio-economic backgrounds, Indigenous students and students in rural and remote communities bear the brunt of funding inequities,” Haythorpe said.
An analysis of the latest results by the AEU and the education group Save Our Schools reveals achievement gaps of two years or more in reading, writing and numeracy between Year 5 students whose parents are highly educated and students whose parents have a limited education.
“Those gaps widen as a student progresses through their schooling. There is a four and a half year achievement gap between students whose parents are highly educated compared to students whose parents have a limited education for Year 9 students,” Haythorpe said.
“Year 9 Indigenous students face achievement gaps of up to six years in reading, writing and numeracy between when compared with students whose parents are highly educated.
“If we want to close the achievement gaps for our students then we need to target funding to ensure that all schools reach 100 per cent of the minimum Schooling Resource Standard,” she added.
A student survey alongside the test shows about 80 per cent of students see participating in activities to benefit the local community as important.
About three-quarters of students in both year groups reported being interested in global issues and what is happening in other countries.
"The highest levels of trust in civic institutions at both year levels were reported for the police and law courts, while the lowest percentages of trust were found for social media," the Australian Curriculum, Assessment and Reporting Authority's CEO Robert Randall said in a statement.