Maths performance is down in all states and territories, with particularly significant declines recorded in South Australia, NSW, Tasmania, Western Australia and the ACT.
According to outgoing Minister Bytyci, Kosovo will next undergo the PISA assessment in 2021.
On Singapore losing top spot in the rankings, Mr Sng said: "We didn't take part in the Pisa to try to beat every country".
Irish students are also above the worldwide average for science and maths, although, worryingly, the number of Irish teens performing at the highest levels in these subjects is down.
Principals and researchers agree that a declining love of reading and rising classroom disruption could be to blame for New Zealand's poor results in a major worldwide test.
The report said: "In this context, and given the fact that expenditure per primary and secondary student rose by more than 15% across OECD countries over the past decade, it is disappointing that most OECD countries saw virtually no improvement in the performance of their students since Pisa was first conducted in 2000".
Amin added Malaysia's achievement in all three domains also put the country above other Asean countries, except Singapore. The UAE scored 435 in mathematics skills, 432 in reading skills and 434 in science skills.
In Maths tests students from Northern Ireland scored 492, while in science they scored 491 - just above the OECD mean for both of 489.
Education ministry officials have partly attributed the poor performance results in reading to the change, saying that students nowadays are unaccustomed to answering questions using a computer. Compared to the previous such study, the students have come off as less accomplished in reading and science literacy though.
On average across OECD countries, 13% of students in 2018 had an immigrant background, up from 10% in 2009.
The assessment focuses on proficiency in reading, mathematics, science as well as on students' well-being.
Across the assessment domains, there was around three-quarters of a year of schooling difference between students in government schools and students in Catholic schools, around one-and-a-half years of schooling difference between students in government schools and students in independent schools, and nearly one year of schooling difference between students in Catholic schools and students in independent schools.
In the past 12-18 years, New Zealand's scores had declined by 23 points for reading, 22 points for science and 29 points for maths.
The organisation also says that electronic formats have become more common test taking formats, including for reading.
As MOE has put in place measures to reduce the emphasis on grades, he said: "It would be interesting to look at the next Pisa results to see if these changes will change the way parents and students think". In Canada, more than 22,650 students in 914 schools participated.
Top 3 in all three categories for PISA 2018. The results show, the performance of Indigenous students was lower than for non-Indigenous students in all assessment domains.
In reading, the difference in the mean score was 76 points (or the equivalent of around two-and-a-third years of schooling).