Boys are lagging further behind girls in school achievement, with new results showing that a double-digit gender gap has opened up.

Education Ministry figures show that, in last year's National Certificate of Education Achievement, 50 per cent of girls passed level 3, but only 37 per cent of boys did. At level 2, 74.1 per cent of girls passed, and 65.7 per cent of boys.

The results come a day after the Education Review Office reported that about a third of schools were failing Maori students. Education consultant Joseph Driessen said: "Boys will continue to underachieve in our national school system unless the Government makes a considered effort to help address the gender gap.

"If it's true that boys are underachieving and it's true that is going to harm them, and our families and society, then we need to be courageous and take action."

Education Minister Anne Tolley said she was concerned at the gap. There were many theories about it, and boys often caught up at university, if they made it that far. "What it comes down to is making sure we have a flexible, responsive schooling system that is able to cope with a whole variety of students and their needs.

"Some of the boys' schools use a lot of physical exercise and some of them have very hands-on learning. Much more hands-on than you would get in normal school."

Single-sex schools had been telling the Government they did better for their pupils, but Mrs Tolley said she did not think a new single-sex school had been opened in years.

The Government had introduced the Youth Guarantee, which provided an alternative for boys turned off by books. The scheme offers 2000 students who have left school free training at a tertiary institution.

Mr Driessen said the Youth Guarantee was a good idea but 2000 places was a "drop in the bucket" for a problem that could ultimately reshape the dynamics of society. More primary schools should take boys-only classes, he said. And while Maori had a commitment from the Government for improvement, boys did not.

The ERO report, issued on Tuesday, said it was "of concern" that not all teachers had recognised their professional responsibility to particularly promote Maori success.

Mrs Tolley said it was "really disappointing" that Maori achievement was not being fully addressed, but the achievement of boys and of Pasifika students was similarly worrying.

"Secondary school is where we lose these kids. The evidence is there as to what works, and it's a matter of schools focusing on a group of students who are failing and rather than saying, `You have to change', the system has to change."

The Education Ministry report showed gradual improvement in overall pass rates for NCEA. In 2003, 52.6 per cent of all pupils passed NCEA level 2, but that was up to 73 per cent last year.

At decile 9 and 10 schools, 85.9 per cent of pupils passed at least NCEA level 2. At decile 1 and 2 schools, only 51.2 per cent passed level 2.