SCOTLAND'S new curriculum requires an overhaul and action is needed to deal with the exam attainment gap between schools in high and low performing council areas, according to international experts.

A raft of key changes to improve the Curriculum for Excellence (CfE) has been called for by the Organisation for Economic Co-operation and Development (OECD).

Amongst the ongoing problems identified were that implementation of CfE was proceeding at varying speeds in different areas.

The international body, which called for action to address the exam attainment gap between the best and worst performing local authorities, also highlighted concern that insufficient use was being made of assessment information to support children’s learning.

The report said: "Too many teachers are unclear what should be assessed.... current assessment arrangements do not provide sufficiently robust information, whether for system-level policy-making, for local authorities or for individual schools."

The OECD went on to warn of a lack of independent research about how well the curriculum was being implemented saying: "There is extensive professional knowledge, but this is not balanced by large-scale research or evaluation projects... by either the universities or independent agencies.

"There is a clear need to know how CfE is actually being implemented in schools and communities across Scotland."

It even suggested CfE should be rebranded to make its purpose clear to parents and recommended the “Curriculum for Excellence and Equity” or “Raising Achievement and Attainment for All”.

The report, commissioned by the Scottish Government, comes as international comparisons show levels of academic achievement in Scotland are above international averages in science and reading while similar to the average in mathematics.

However, while there has been a "clear upward trend" in attainment this has not been the case in mathematics and there has also been a decline in basic literacy and numeracy skills.

First Minister Nicola Sturgeon welcomed the document and said the Scottish Government shared the OECD view that an opportunity existed to "lead the world" in developing an new assessment framework - which includes her controversial plans for national testing.

She said: "I firmly believe the framework will play an important role in driving work to close the attainment gap and continually improve Scottish education."

However, Dr Alan Britton, a senior teacher at Glasgow University's School of Education, described some of the report's findings as "positive, but naive".

He said: "The OECD has proposed an enhanced role for local councils in the further development of CfE, but it does not take into account the fact that the bulk of local authority staff who used to play an important role in curriculum development and training are no longer there because of ongoing cuts.

"There is a lack of understanding in this report that there is very limited capacity in local authorities to lead this development work so the burden will fall on national bodies who are not always based placed to lead localised improvements in schools."

Larry Flanagan, general secretary of the Educational Institute of Scotland (EIS) teaching union said the report confirmed that Scottish schools and levels of pupil attainment compared well internationally and with other UK countries.

"It also highlights the well-established challenges facing Scottish education, including the poverty-related attainment gap that continues to have a negative impact on too many young people across the country," he added.

Liz Smith, Scottish Conservative young person spokeswoman, said: "The OECD report confirms there are major issues in numeracy and it sends out a very stark message about addressing failing schools.

"A range of recent statistics prove the extent of the attainment gap and the fact that literacy and numeracy are not as strong as they should be."