A four page report by the International Council of Education Advisers (ICEA) says there needs to be a “systematic, sequenced and selective plan” for literacy and numeracy.
Opposition politicians said the report confirmed that the Scottish Government had failed to deliver the improvements that the public expected in Scotland’s schools.
The ten person group, including experts from Canada and Malaysia, have been flown to Scotland for two trips at a cost of £60,000 since their appointment last year.
The report identified three priorities: improving teaching of specific subjects; developing leadership at all levels of the education system and ensuring collaboration takes place.
The report follows criticism of the Scottish Government’s stewardship of education after Scotland dropped down international league tables when it came to literacy and numeracy standards.
Parts of the report were seen as a criticism of the Scottish Government’s school reforms to give more power to teachers and to impose more tests on children.
The ICEA advised “against becoming too focussed on changing the structure of the education system when, arguably, the more important aspects are the culture and capacity within the system.”
The council also warned there was “a risk” that education policy was moving away from the “whole child” approach of Curriculum for Excellence to “a more specific, measurable approach”.
Shadow Education Secretary Liz Smith said: “The long and short is the fact that the Curriculum for Excellence has, so far, failed to deliver the improvements in Scottish education that everyone wants to see.
“This is because the Curriculum for Excellence is ill-defined and its delivery under the SNP has been a complete mess.
“Addressing this issue must surely be the priority of the ICEA since it is so strongly related to attainment.”
Labour’s education spokesman Iain Gray said: “John Swinney spent tens of thousands of pounds flying-in his council of international experts to produce a four-page report which confirms the growing concerns about the SNP’s stewardship of our schools.
“When you read between the lines, it’s quite clear that the experts are concerned about the literacy crisis in our schools and want ministers to urgently focus on improvements.
“And rather than introduce Thatcherite governance reforms in our schools, the experts are right to point out that capacity in the system is key. That’s obvious when you consider that 4,000 teachers have been lost under the SNP.”
Lib Dem education spokesman Tavish Scott said: “It directly criticises the SNP’s dangerous focus on the restructuring of the education system and more testing of children.”