Scottish pupils missed nearly a million days of term time due to unauthorised holidays in the last year, according to new analysis.
When all forms of unauthorised absence from schools, including truancy, are included, almost two million school days were missed by pupils last year, Scottish Labour said.
Scottish Government figures showed 0.7% of pupils missed school due to unauthorised holidays in 2016/17, up from 0.5% in 2014/15.
Labour calculate this amounts to 910,272 lost school days last year.
In 2016/17 1.5% of pupils missed school due to unexplained absences including truancy, up from 1.3% in 2014/15.
According to Labour calculations, this amounted to 1,950,583 school days lost last year.
The party said the increase in recent years should be a cause of concern for the SNP government and may undermine attempts to close the attainment gap.
Scottish Labour education spokesman Iain Gray said: “These figures should be a cause of concern for any government that wants to close the attainment gap on our classrooms, a huge amount of school days are being lost.
“Policymakers in the Scottish Government should be asking themselves why there has been such a sharp increase in these unauthorised absences and the knock-on effect that will have on young people getting the skills they need.
“We know the pressures families fall under as the Christmas and summer holidays approach – airlines hike up the price of flights, forcing families to choose between the last week of school or being able to afford a holiday or travel to see loved ones.”
Schools will not normally give a family permission to take pupils out of school for holidays during term-time.
The education authority can issue attendance orders under section 38 of the Education (Scotland) Act 1980 and if they do not comply, the parent can face prosecution in the sheriff court and a fine or imprisonment if they are found guilty.
A Scottish Government spokesman said: “Although only around 0.7% of half day sessions were lost to unauthorised holiday absences in 2016/17, it is important that schools and parents continue to do all they can to ensure good attendance to maintain children’s attainment.
“The Scottish Government will continue to support local authorities, schools and parents to do all they can to ensure good attendance in addition to our considerable investment in raising attainment.”