Zonta Club of Metropolitan Dunedin Lynette Grave said orange was the colour representing International Day for the Elimination of Violence Against Women, which was observed on November 25.
It marks the start of 16 days of activism, which is how long the lights will be orange.
People often looked up at the floodlights around town and did not know what they were representing, so she hoped having a series of orange around the city would inspire people to look into it and learn about the issue.
It also served as a way to remind women that violence was not acceptable and they could seek help.
Zonta is an international service working to improve the lives of women.