Australia has shot up the international rankings in Year 4 reading ability.

The Progress in International Reading Study (PIRLS) ranked Australia 21 out of 50 countries among Year 4 students, up from a ranking of 27 in 2011.

Singapore, Russia, Northern Ireland, England, Ireland and Poland were the top performers.

Australia was ranked near the USA and Canada, outperforming other countries including France, New Zealand and Spain.

But it is not all good news, with the same study showing that among students in the low-performing 20 per cent, Australia has barely budged.

Australian Council for Educational Research CEO Dr Sue Thomson says there were some pleasing findings.

“I think this is the first time I've been able to report on one of the international studies where the results have actually improved,” Dr Thomson said.

“I think that we should be pleased that we have done something to address what was flagged as a real issue in 2011, and that our top level seems to be improving.

“But on further analysis there is still a lot of work to be done.

“The big issue is the proportion of students who are still not reading at a proficient standard for Australia or internationally, and the fact that it's still based on equity grouping, so it's still lower SES (socio-economic status) students and Indigenous students who are missing out.”

Fifty-seven per cent of Indigenous Year 4 students met or exceeded the intermediate international benchmark, compared to 83 per cent of non-Indigenous students.

Federal Education Minister Simon Birmingham said the study shows the size of the task ahead in lifting literacy performance.

“Australia can be proud of the quality of our schools, the work of our teachers and the entire school system, but we should keep striving to do even better because that's what will guarantee our competitiveness in the future,” he said.

The Federal Government is using the report to support its reforms to teacher quality, simplification of the school curriculum, and focus on basic literacy skills.