Students at NSW public schools are struggling with out-of-date computers and slow wireless networks and the key program that provides technology to all schools has not had a funding increase since 2004 despite soaring enrolments, a new Auditor General's report reveals.

Many teachers are not provided with computers to use outside the classroom for lesson planning, and the NSW Department of Education does not know how many schools have implemented a Bring Your Own Device scheme for students or how many teachers have devices, the report says.

A new audit report says funding for technology in NSW schools has not increased since 2004.

The report also warns that the department is "not sufficiently monitoring the digital literacy of NSW students, which has declined in national tests".

About half of all the computers in schools are at least five years old and about one in eight are from the last year of the Commonwealth's Digital Education Revolution program, which provided laptops for year 9 students from 2009 to 2013.