Nearly a third of government high schools in Sydney are "neither efficient nor effective", according to a new study that finds poor use of resources by schools is often linked to students' low Australian Tertiary Admission Ranks.

The study of 339 secondary schools across NSW found that schools in Sydney's south-west were most likely to use funds and resources inefficiently and produce low ATARs, while those in Sydney's north were highly likely to be efficient and perform above average in the Higher School Certificate.

About 45 per cent of schools in Sydney's south-west were found to be inefficient.

The paper, which was published in the Australian Journal of Education, measured efficiency by a school's ability to lift students' HSC performance based on their year 10 results, socioeconomic status and school funding. It tracked students' performance between years 10 and 12 at each school over five years from 2005 to 2010, using data from the NSW Department of Education.

About 45 per cent of schools in Sydney's south-west were found to be inefficient and the average ATAR for the area was 49.19, well below the Sydney-wide average of 58.60.