The latest study was undertaken in early 2014. ERO sent it to the ministry in February this year after peer-review and consultation.
Initial communications plans were drafted, but it sat in limbo until July, when ERO decided to make it public. The report was sent to the minister's office on July 31.
Its imminent release sparked a flurry of activity at the ministry, including meetings with ERO and internal "war-room" sessions about risks.
On August 5, the contents of the report were leaked to the Herald. It was put online later that night.
A communications plan sought to focus media attention on "good stories" and ensure the public perceived Early Childhood Education as "high-quality".
Green MP Catherine Delahunty said it appeared the ministry was trying to hide a problem to make the minister look good. "How can parents trust information about services if they are whitewashed?"
In releasing the OIA documents, the ministry itself identified its actions could be viewed as a "cover-up", rather than focusing on supporting providers to lift achievement.
It mitigated that by providing information to the Herald saying that a communications plan, like the one for the ERO report, was part of any data or research release.
Responding to questions about the communications strategy, Ministry of Education deputy secretary Rawiri Brell said it was always looking to share news about early childhood services.
"War-room meetings" were held when the ministry needed to bring together people within a tight timeframe to respond to a topical issue, he said.
Mr Brell said the ministry had taken "more time that we would have liked to" in replying to ERO about the draft report, but had taken steps to ensure its responses were within a more effective timeframe to assist ERO in future.
• An earlier version of this report said the ERO report was partially rewritten after high-level meetings about its risk to the Government. While the sequence of events is correct, the Herald would like to clarify that there is no connection between them, the Ministry of Education did not seek improper influence over the ERO, an independent agency, and that the changes - to some of its recommendations - were not made as a result of external pressure or ministry meetings. We apologise for any such inference.
Source documents:
Ministry of Education correspondence about infants and toddlers report