"There could've been 80 people in there earlier in the day," Church said. "The debating chamber was absolutely full in the morning from a staff meeting."
Around 150 staff work at the two storey building. The driver narrowly missed steel beams which clad the building.
"The crash was a very unusual occurrence, it caught us off guard. Everybody knew how to react."
Church said the driver appeared to be about 50 years old and was not badly hurt. The driver passed a breath test at the scene.
"We were very lucky there were no staff in the council chamber. Eight chairs got knocked over that could have had people in them."
Church said the building, which has 150 staff, was fully refurbished a year ago.
Two concrete pillars 6m apart reinforce the building along with A-shaped steel beams.
Two of the cars hit by the driver on Rimu Road were written off.
"The car's gone between the beams," Church said. "It would've been worse for the car if it had hit the beams. The wall has absorbed a lot of impact.
"We dealt with it very quickly because there were a lot of council staff around. There were road engineers and first aid people so instantly three people phoned 111."
The wall now sports a temporary patch "Which doesn't look too bad," Church said.