The advantages of a private education dissipate once a student enters university, according to a new study.
The findings reinforce the case for giving state-educated pupils lower offers for entry to university courses than private pupils, researchers from Monash university said.
"These results ought to cause some tremors among higher-education policy makers," said the researchers. "Bright students from government schools are disadvantaged in Year 12 (the final year of secondary school)."
The study of students beginning university courses between 2000 and 2003 found those from state schools achieved significantly higher marks in their first year than counterparts from private and Catholic schools with the same entry scores.
As in the UK, Australian universities currently admit a far higher proportion of applicants from private schools, who generally have higher entry scores than those from state schools.
But state students with lower entry scores performed as well as those from private schools with much higher scores.
The researchers say the findings have significant implications for universities' admissions and equity policies. They suggest that universities should give students extra credit for their exam scores when places are being allocated.
The researchers say their findings are consistent with the argument that private schools "add more value" than government schools. But once on the "level playing field" at university, state students tend to do better.
They note that research by the Higher Education Funding Council for England in 2003 also found that while government-funded schools achieved lower A-level grades than private schools, the state students did better at university. "As reported by the BBC, some commentators argue that pupils from state schools should be given lower offers than those at independent schools," said the Monash researchers.
They report that in Victoria in 2002, independent-school students represented less than 20 per cent of all final-year students who applied for a university or technical college place. Yet they made up 35 per cent of those admitted to Monash in 2003.
Similarly, Catholic school students made up 22 per cent of all applicants, but won 25 per cent of the Monash places.
State-school students made up 59 per cent of those applying for university but only 40 per cent of those admitted.