They were allowed to return just over an hour later after the source of the suspected gas leak in central Dunedin was discovered.
Hundreds were evacuated after the smell of gas spread through multiple buildings in Great King St.
Fenz Otago Assistant Commander Rob Torrance said the leak had been tracked to contractors carrying out testing nearby.

Two blocks of buildings housing University of Otago health sciences departments were evacuated just before 1pm.
A spokeswoman for Fenz said two representatives from Genesis Gas was working through each affected building and clearing them.
Once the buildings were fully cleared, people were allowed to re-enter them.

A group of students told the ODT they were at a lecture in the Hercus Building, in Great King St, when they smelled a strong odour of gas.
They were evacuated soon after.

This involved hundreds of staff and students.
All University buildings have since been cleared and re-occupied.
Six fire appliances including a command unit were at the scene.
Part of Hanover St was blocked as crews responded.