Stage fright, heat and the flu could have been the ''overwhelming'' factors causing children to faint on an Invercargill theatre stage yesterday.
St John South Island communications adviser Ian Henderson said after reports of several children fainting, four ambulances and a rapid response vehicle were called to the Civic Theatre in Esk St about 1pm.
The ambulances transported nine children, aged from 10 to 12, to Southland Hospital's Emergency Department.
At least six of the children were in a moderate condition. Several children were assessed at the scene.
A Southland Hospital spokeswoman said all the children had been discharged by last night.
Theatre manager Kate Feaver said emergency services were called after 12 children fainted on stage when rehearsing for last night's ILT School's Singout.
The cause of the fainting was undetermined, but a mix of stage fright and the heat on stage could have been factors.
''It's not uncommon for children in large groups to get a little overwhelmed in the environment.''
A child who fainted, who recently had the flu, started a ''chain reaction'', with more children fainting soon after.
The children affected were from several different schools, she said.
The heat generated from about 200 performers on stage, combined with heat from stage lighting, may have been factors. However, the theatre heating was turned off at the time, Ms Feaver said.
Children had fainted at similar events in the theatre before and she could not rule out it happening again.
''You are dealing with children standing on stage and they do get a little bit overwhelmed. So it's something you can't rule out completely - you can't stop it happening.''
The other children were evacuated from the theatre and returned to their schools by bus, Ms Feaver said.
A Fire Service spokesman said firefighters from Kingswell Station were called and no gas leak or fire was found in the theatre.
Police cordoned off a block of Esk St, at the rear of the theatre. Ambulance staff, dressed in protective clothing, ushered blanket-clad children into the ambulances.
Staff and visitors were stopped from entering or leaving the neighbouring Invercargill City Council building for about 40 minutes.
