CHILDREN as young as eight are being coached by private tutors in how to pass the tests that form the basis of performance ratings on the My School website.

The pressure to do well in the National Assessment Program Literacy and Numeracy (NAPLAN) has spawned cramming courses designed to help students pass.

Alpha Omega Education, one of the groups running a NAPLAN boot camp, offers one-day workshops or term-long coaching.

School principals warned that NAPLAN had become such a high-stakes exam that external supervisors may be needed to police classrooms when students sit the tests from May 11 to 13.

The NAPLAN results decide whether schools' academic performance is coloured green or red on the My School website.

Secondary Principals Council president Jim McAlpine said yesterday serious damage could be done to the reputation of schools in the low-achieving red band.

There is pressure on schools to get the best results . . . we will need processes in place to ensure the legitimacy of the tests, he said.

The council has asked the Australian Curriculum, Assessment and Reporting Authority to review NAPLAN procedures including increased security of test materials. Principals have heard claims of fraud, including one student at a non-government school in Sydney's north invited to the principal's office to change his results.

That was the starting point for a lack of confidence in the testing process, Mr McAlpine said.

We have to be confident students are being tested on their merits rather than being helped.

Primary co-ordinator Rabiha Kanj said demand for NAPLAN coaching had risen sharply since the My School website was launched in late January.

We're trying to cover all the content that they've learned and teach them how to interpret problem-solving questions in the exams, Ms Kanj said.

A lot of children, especially those from non-English speaking and lower-socio economic backgrounds, find it difficult to interpret those types of questions.