The education policy to assess children aged between five and 12 as either at, above, below or well below set standards in reading, writing and maths has been National Party policy since before the 2008 election and has been in use in schools since 2010.
Schools were expected to set targets in their 2011 charters and were required to report to parents in writing at least twice a year about their child's progress.
Schools were required to send national standards data to the Education Ministry in May and data was intended to be presented by the ministry in September.
ERO recommended the Ministry of Education continue to help school boards fully understand their responsibilities for the requirements of the National Administration Guidelines and national standards - in particular how the standards could help set targets to raise achievement.
Ministry of Education group manager Frances Kelly said there was an ongoing programme to embed national standards.
"The ERO report suggests some schools may need more support than others to do this. The ministry is continuing to support boards and schools to improve learner progress and achievement, particularly for priority groups.''
"Based on the information received, the ministry expects to provide a report on learner achievement in September.''
Prime Minister John Key said on yesterday the data coming in was unlikely to produce satisfactory data and it needed more time.
New Zealand Educational Institute president Ian Leckie has called for a law change to prevent the publication of the data.
"We would be very happy to talk to the Government about the ways in which the data could be safely used for its original purpose of supporting teaching and learning. But we are not prepared to take part in any face-saving measure that would involve public release of this unreliable data.''
Labour spokeswoman for education Nanaia Mahuta said the Government's plan to introduce league tables could give parents a blurred picture.
"League tables, drawn from National Standards, publicly rank schools on a few select criteria, but don't give the full story. Without proper context and moderation some schools may be unfairly labelled as under-achieving and parents will be fed misleading information.''
Green party education spokeswoman Catherine Delahunty said the Government should step in to stop the media using national standards data to create league tables.
"The media will use the information they have and it will be an inaccurate description of the quality of education in any given school. The league tables will probably resemble the secondary tables based on NCEA results but based on even less robust information.''