In a letter sent home to parents, the board of trustees said it had been notified by Opus International Consultants Ltd that it was unrealistic to expect the upgrade of the existing buildings to be completed by January 27 next year.
"For this reason, the College Street site will need to remain operational for term one of 2012, with the proposed redevelopments to be completed by March 30, 2012," the letter stated.
"Once the principal and staff appointment processes have been completed, we will be able to provide you with more information regarding how the current College Street site will be utilised."
The news was not unexpected for the principals of the schools, who had already aired concerns about the Ministry of Education's time frame for the merger.
College Street School principal Gary Tenbeth declined to comment on the situation yesterday.
He said the board's focus now was to create a campus with a 21st-century style which would give pupils an education for the future that was "not hindered by the past".
"Modern learning environments are certainly part of this.
"We want our students and teachers to have the best possible environments for learning and teaching."
The newsletter said the Calton Hill site classrooms needed to be freshened and some other refurbishment done.
At least two new classrooms and a library would be built as part of the redevelopment at the Caversham site.
The board is also consulting the Dunedin City Council about pick-up and drop-off zones outside the school, pedestrian crossings, regular visits from the Book Bus, spotlighting of the memorial gate, upgrading the fence along the lane at the back of the Caversham School, and drainage of the field so it can have greater use.
The Ministry of Education has approved Otepoti South School as the new name of the merged schools.
However, parents will again be consulted on the proposed name, and after feedback is considered, the board will make its final decision.
