Brendan and Chota Moore observed the cloud from their Chain Hills home.
Merv Chave saw the cloud above South Dunedin
Peter MacDonald referred to the cloud as a "chem trail from a US military aircraft".
Sue Skilbeck's view from her Brighton home.
Kirstin Quin's view over Andersons Bay at 9am.
David Fynmore's photo at 9.20am.
Nicolle Vincent also thought it was a military plane. This frame-filling photo taken at 9.25am.
Malcolm McMartin's view over Dunedin at 9.28am.
By 9.43am, Malcolm McMartin's view had changed as the cloud widened and dispersed.
Brett Doherty's view above Dunedin Airport, 9.28am.
Brett Doherty also watched the cloud disperse; this picture is at 9.51am.
At 10.30 am a faint, thin line was barely visible above Chris Rietveld's workplace in Kenmure.
Otago Daily Times readers share their photos of the unusual cloud formation, believed by many to have been an aircraft vapour trail, seen over Dunedin on Thursday morning.