Younger pupils are becoming victims of parentally condoned truancy - particularly girls, a leading expert said this week.
Professor Ken Reid, chair of the national behaviour and attendance review (NBAR) in Wales, said pupils as young as six were being kept regularly at home.
And he said research revealed that lonely mums who kept their daughters home to go on shopping trips were among some of the biggest culprits.
Latest figures released this week by the Assembly government show attendance rates at Welsh primary schools improved slightly in 20067. But they are still well up on England, with rates of unauthorised absence almost double.
Professor Reid, deputy principal at Swansea's Metropolitan University, said increasing use of education welfare officers at primary level had contributed to a welcome rise in attendance rates at schools in Wales's cities and larger towns over the past 12 months.
He said the NBAR, which had made high absenteeism rates in Welsh primary schools a major concern, had acted as the catalyst.
In 2007, 0.9 per cent of all half-day sessions were missed through unauthorised absence, a fall from 1.0 per cent in 2006. Last year, 6.9 per cent of all half-day sessions were missed through overall absence - down from 7.9 per cent.
The rates are still better than at secondary level in Wales, but experts see tackling growing absenteeism as all-important in attacking disaffection and low achievement in later life.
In his own analysis, Professor Reid said the most marked improvement had been by local authorities targeting primary schools, with Cardiff, Bridgend and Merthyr Tydfil doing particularly well.
"It is encouraging that most of the bigger authorities have reduced their overall rates well," said Professor Reid. "The decreases in Bridgend are most impressive."
However, the wide variations in schools' absenteeism problems continued to be a worry in Wales. He said there could be as much as a 4 per cent difference between rates in schools in the west and east of Swansea.
As with previous figures, areas with more free school meal entitlement have higher truancy rates, something Professor Reid says has been a product of parental choice.
"These general statistics, released this week, don't really tell the full story," he said. "We need to look at the absenteeism rates of individual schools to get a better picture.
"Parental choice means that some schools' figures are going up."
Writing in TES Cymru last year (November 9), the academic said it had become clear to his team that primary school absenteeism needed to be addressed. But he warned this week against "victimising" parents in winning the battle.
Research undertaken last year in Wales found that most teachers do not think jailing parents, handing out on-the-spot fines or anti-social behaviour orders will help.
Professor Reid said parents who took their children on cheaper holidays during term time were misguided but were only contributing to around 15 per cent of unauthorised absence overall.
The NBAR's full findings, the result of two years' work, are expected to be published this April.