A report has found that 20,000 pupils in Northern Ireland missed the equivalent of six weeks of school in 2011/12.

The figure is double that of children who miss lessons in England, according to the Northern Ireland Audit Office.

On average, the absence equated to each primary school pupil missing nine days a year, and secondary school children missing 13 days a year. In addition, those living in higher poverty areas, such as in state care or from Traveller families, were more likely to skip classes.

Despite the high figures, the report said that less than 4,000 pupils were referred to the Education Welfare Service for their non-attendance, with 80% (16,000) not referred to the specialist support service.

Elsewhere, it was revealed that absent children are more likely to fail exams and are seven times less likely to be in education, employment or training by the age of 16 than those who regularly attended lessons.

The report said that progress has been made on the issue since the last audit report was carried out in 2004, but the level of unauthorised absence has increased and now accounts for a third of all absences.

The auditors of the report said the high levels of absence was "disturbing".

Kieran Donnelly, Auditor, said: "Regular school attendance and educational attainment are inextricably linked.

"It is therefore disturbing that around 20,000 pupils missed more than 15% of their lessons in 2011-12. This equates to six weeks of schooling.

"Although pupil attendance has improved since 2007-8, levels of unauthorised absence remain a challenge and a number of disparities in attendance rates persist across several groups of pupils.

"It is vital that all our children attend school regularly and make the most of the opportunities that the education system offers to them.

"This will not only improve the life chances of our young people but will also ensure that our economy is well-equipped to compete in an increasingly global marketplace."

In addition, the report set out 14 recommendations on how to improve attendance levels, such as the tougher monitoring of absence, referring children to support and the education and library boards working better with the Department of Education.

(JP/CD)