Investment in computers and iPads in schools does not improve numeracy and literacy skills, a new OECD report has warned.

In fact, the report, just released by the organisation which is considered the definitive authority on global academic performance, found frequent use of computers in schools is often associated with lower results.

The first global study on students' digital skills shows Australia is one of the highest users of technology in schools.

Yet the country's reading and maths performance has declined over 2000 to 2012, based on data from 2012 Programme for International Student Assessment.

There was "no appreciable improvements in student achievement in reading, mathematics or science in the countries that had invested heavily in (information technology) for education," said the Students, Computers and Learning: Making the Connection report.

And where the technology is used in the classroom, the impact on student performance is "mixed, at best".

"Put simply, ensuring that every child attains a baseline level of proficiency in reading and mathematics seems to do more to create equal opportunities in a digital world than can be achieved by expanding or subsidising access to high-tech devices and services," the report said.

Schools adopting technology in the classroom would fail to improve results, if teachers were stuck in "20th century teaching practices".

Between 2003 and 2012, students' performance in mathematics deteriorated in most countries - including Australia - where there were more computers in schools.

Students in countries using fewer computers for schoolwork improved more rapidly in reading.

"If students use smartphones to copy and paste prefabricated answers to questions, it is unlikely to help them to become smarter," the report said. "If we want students to become smarter than a smartphone, we need to think harder about the pedagogies we are using to teach them. Technology can amplify great teaching but great technology cannot replace poor teaching. "

Australian students spend nearly an hour on the internet when they are at school, which is more than any other country and twice the amount of the OECD average.

Australian classrooms also have the highest proportion of students using computers at school.

This will be a sobering report for Australian policymakers, as the goal of a computer for every student is often sold as the solution to low grades and disadvantage.

"In the past 15 years, schools and families around the world spent a substantial amount of money on computers, internet connections, and software for educational use. Yet the benefits of these investments for children's learning are not clear," the report said.

"Students who use computers moderately at school [once or twice a week] tend to have somewhat better learning outcomes than students who use computers rarely. But students who use computers very frequently at school do a lot worse in most learning outcomes."

Technology can be a useful tool in class, the report found, as it enables teachers to tap into specialised materials beyond the standard textbooks and to run innovative learning projects in class.

Keysborough College principal John Baston said there was no point using  technology in schools if teachers were not taught how to use the devices effectively in class.

He said every student at the school used an iPad or computer in class. Educational computer programs were used to help target the students' work, so that it catered to the students' academic ability.

"The computers are there to enable you to help improve teaching, but it can't create by  itself quality teaching," he said.