Hundreds of people have been caught up in a privacy breach after the Otago Regional Council broke confidentiality and shared their email addresses - twice.

Council deputy chief executive Amanda Vercoe has apologised to the 472 people whose email addresses were mistakenly shared after they submitted on the draft regional public transport plan.

On Thursday, the council sent an email to submitters, acknowledging their submission and giving details about next steps in the consultation process.

The submitters’ emails were inadvertently copied into "To" instead of "Bcc" - making submitters’ email addresses visible to everyone else, Mrs Vercoe said.

A second email, recalling the first, had the same problem and a full list of submitters’ emails was included.

Mrs Vercoe said people were told their names would be public when making submissions, but not their email addresses.

"We’re very sorry for this error and regret that it occurred," she said.

"It was a genuine mistake, and we hope that it did not cause any undue alarm, distress or confusion to any submitter."

On Friday, the council contacted submitters and apologised - acknowledging the privacy breach and asking they delete the emails and not share them.

"Submitters were also told, and given contact details, that if they wished to complain that their privacy has been breached by council, then contact ORC.

"Also, that if they wished they could contact the Office of the Privacy Commissioner," she said.

The council was looking to increase future checks and balances so the mistake was not repeated.

A fresh email was sent to acknowledge the submissions and next steps regarding the consultation process.

ruby.shaw@odt.co.nz