Mr Barclay made the announcement at Te Anau Primary School this morning, on behalf of Associate Education Minister Nikki Kaye.
The investment would help the school cater for projected roll growth, as more families were moving into the Te Anau area, Mr Barclay said.
“Te Anau Primary School has experienced steady growth over the past three years and this trend is expected to continue,” he said.
The school’s roll grew from 189 in October 2013 to 252 in 2017.
“This growth was greater than anticipated and has created pressure on school facilities,” Mr Barclay said.
The two new teaching spaces will be modular buildings - modern, permanent structures which are more adaptable.
The $800,000 announced today comes on top of around $36 million announced last June for school property in Clutha-Southland.