Dunedin Mayor Dave Cull said that since yesterday’s announcement about the vigil - scheduled to start at 7pm on Thursday - word had reached the council that large numbers of people were expected to attend, including thousands of tertiary students.
Mr Cull said it was really heart-warming that so many people wanted to turn out.
"However, that means we’re likely to outgrow the Octagon, which was the original location.
“To make sure we can include everyone who wants to take part, we need to have a really big venue and the stadium is ideal as it can safely hold more people than the Octagon.”
The vigil, organised by the council and Amnesty Otago, was a chance for residents to ''put their arms around each other'', Mr Cull said.
It was announced yesterday that the vigil would be held in the Octagon.
Late yesterday, Mr Cull confirmed the venue was now being ''reconsidered'' because of anticipated numbers. It was thought up to 30,000 people could attend.
The shift to the stadium was announced this morning.
Mr Cull said the city was ''grieving and in shock'', and the vigil would be ''an important way to support our Muslim community and the broader community''.
''We need an opportunity for our residents to put their arms around each other at this tragic time.''
He urged people to join the vigil to show ''solidarity and support, and to demonstrate the resilience and love of the Dunedin community''.
The vigil would build on an event already being organised by the Otago University Amnesty International Group, which had been planned for Thursday.
It would now instead become the civic vigil, co-ordinated by the council.
The crowd was expected to be swelled by a University of Otago event being staged immediately before the civic vigil, he said.
The thousands of students expected to attend that event would be encouraged to attend the civic vigil as well, Mr Cull said.
The DCC and Amnesty had worked closely with the Muslim community and other organisations, including the police, the Dunedin Multi-Ethnic Council, the Dunedin Interfaith Council and the Otago University Students' Association, in planning the event.
Mr Cull said the response to Friday's ''appalling and cowardly'' terrorist attack in Christchurch had been emotional.
''It's been heart-wrenching to see Dunedin residents express their support in a range of ways over the weekend, from gatherings to small acts of kindness. I'm incredibly proud of our community.''
The council had wanted to organise a vigil earlier, but with members of Dunedin's Muslim community in Christchurch at the moment, it had to wait until Thursday, he said.
The vigil would begin with a manawhenua welcome and include speeches by Mr Cull and representatives of the Muslim community, as well as prayers from faith groups across the city.
There would be a strong police presence at the event, Mr Cull said.
