Nicola Sturgeon made the pledge as she opened the Teenage Cancer Trust's ninth international conference in Edinburgh.
Report: 29% Fall In Teachers In Scots Nurseries
The number of registered teachers working in nurseries and pre-school settings has fallen by almost a third over the past decade, according to a new report.
The trend contrasts with a 4% fall in child numbers and comes as the Scottish Government places more emphasis on early learning and childcare.
The research, conducted by the child's curriculum group for the Educational Institute of Scotland (EIS) teaching union, found a 29% reduction in General Teaching Council for Scotland-registered teachers employed in such services, down from 1,702 in 2005 to 1,212 in 2014.
Child numbers fell from 105,810 in 2005 to 101,463 in 2014.
This translates as a ratio of one teacher to 84 children, compared with a ratio of 1 to 62 a decade ago.
The government has pledged to increase free childcare and early-learning hours for three and four-year-olds to 1,140 hours per year by 2020.
EIS education committee convener Susan Quinn said: "This new independent report confirms the importance of maintaining a registered teacher workforce in all pre-school settings.
"It highlights the added value that specialist early-years teachers provide in nursery establishments while also questioning the varying commitment by councils across Scotland to the deployment of teachers in nurseries.
"The report also highlights the ambiguous interpretations of 'teacher presence' and 'access to a teacher', which is particularly important in light of the planned expansion of the early learning and childcare entitlement to 1,140 hours by 2020.''
She added: "Scotland's Curriculum for Excellence offers an enhanced learning experience for young people of all ages, supported by a seamless curricular model from age three to age 18.
"This means that it is even more important for an appropriate level of teacher involvement in all nursery settings.''
Conservative MSP Liz Smith said: "The First Minister made a very firm commitment when she said that her top priority was to close the attainment gap and that the most effective work has to be done in the earliest years.
"A significant decrease in nursery teacher numbers will surely make this commitment impossible.''
A Scottish Government spokesman said: "The Scottish Government values the role of teachers working within early learning and childcare settings and remains committed to ensuring all those children benefiting from the funded entitlement have access to a teacher.
"The First Minister announced in October that from 2018, all nurseries in deprived areas should have an additional graduate with early learning and childcare expertise working with young children.
"In addition, the Scottish Government continues to fund the universities of Aberdeen and Strathclyde to deliver early years-specific Masters qualifications for primary teachers, to provide opportunities for teachers to specialise.''
But Labour's Iain Gray said: "This expert report highlights the importance of access to a teacher in the early years, but the drop in access to a qualified teacher at this vital stage in a child's development is nothing short of staggering.
"We know there is a 14 month gap in development between the richest and the rest in primary 1. We need to close that gap, not allow it to get wider.
"The SNP budget will mean huge cuts to schools and local services. Labour believe the education budget should be protected in real terms for the next five years, but the SNP refuse to back us.
"Instead of accepting cuts we can invest in our future.
"Faced with that choice between brutal cuts to schools and public services or using the powers of the Scottish Parliament, Labour would use the powers of the Scottish Parliament.
"Labour would set the Scottish rate of income tax 1p higher than the rate George Osborne set so we can make a fairer choice to stop cuts to vital services and invest in our country's future.''
The 25 year old from Scotland was found dead on Saturday.
Major cities across Britain are becoming home to "hipster hotspots'' - pushing up house prices strongly in places such as Bristol, Manchester and Edinburgh as well as in London - research has found.
The Convention of Scottish Local Authorities (Cosla) has said that any more cuts to local government funding will result in "severe consequences'' for jobs across the country.
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