That is despite staff use of an online auction site and other sites being significantly less extensive than initially thought.
The Otago Daily Times was provided figures by the council on Thursday in response to a request about which internet sites staff visited most frequently.
It has emerged that because of technicalities with the way the site visit figures were tallied, the figures supplied to the ODT - which showed Trade Me as visited 535,647 times by council employees last month - overstated visits to the online auction site and to other sites.
Council network services manager Tim Oaks said the technicalities, which involved the network counting as hits a large number of other components on a site as it was opened, meant the council was unlikely to be able to isolate what actual site visit numbers were.
In an email sent to all council staff yesterday, chief executive Paul Orders said the bottom line was that the figures provided were "significantly" overstated and "in many ways meaningless".
However, the matter had touched on an important issue.
He had studied the council's policy on acceptable internet use, and did not believe it represented sufficiently clear guidance for managers and staff in a public service organisation.
"Personally, I have a problem with private, non-work related use of the internet during work time. I have therefore asked for this matter to be reviewed as a priority."