The Otago Daily Times yesterday asked the ministry for an update on the development of the block, as construction was due to begin in September or October last year.
Head of education infrastructure Kim Shannon, of Wellington, said the project began last September and ministry staff had been working with the school to plan the work in a way to minimise disruption.
''It was crucial the design plans were carefully reviewed to ensure the building is robust and fit for the conditions in Arrowtown and that it is constructed in the best position to allow future infrastructure development at the school,'' Ms Shannon said.
''A review was completed in March 2014 and we are confident the building will meet the very best quality and weather-tightness standards.''
Tenders would close on April 11 and the ministry expected construction to begin in May, she said.
''The new classroom block should be ready for the beginning of the 2015 school year. This is a relatively normal timeframe for a project of this size and we want to make sure the school is getting good quality teaching spaces for its students.''
The ministry provided a further $305,000 to remove two relocatable classrooms and place another relocatable classroom on the site, which would remain to provide for a roll increase of 25 pupils.
School principal Robin Harris said yesterday building consent was being ''lodged as we speak'' and the planning stage always took longer than first thought.
''It is quite a big process to work through, but it's still this six-classroom block, including a larger space for the library to be relocated, and modern learning environments of open spaces,'' he said.
''It's going to be the centrepiece of the school.''
Mr Harris said there were about 470 pupils at Arrowtown School. However, there were about 510 pupils by the end of 2013 and as many pupils are expected by the end of this year, due to the intake of juniors.
''If the school population keeps growing as it is, then [the block] will be needed over a period of three to five years.''
