Newly released images - designed to give an idea of the building's bulk - show a less extensive and less curvilinear design that extends to the opposite side of Harrop St.
But the group set up to oppose the project said it was headed for the Environment Court, despite the reduced bulk.
Hands off Harrop spokes- woman Judith Indelicate said she had a "very, very cursory" look at the report.
Any chance the changes might soften the stance of the group were scotched by Mrs Medlicott's response to what she saw, which was that she was still "immovable, implacable and obdurate" in her opposition.
The Dunedin City Council has been considering a redevelopment of conference and event facility the Dunedin Centre at the Town Hall since 2001, and designs put together for the council showing a glass atrium raised strong opposition.
A peer review of the project released last week recommended the extension be smaller, and that the land between the Dunedin Town Hall and St Paul's Cathedral be turned into a public space.
Despite three days of heated opposition to the extension at this week's annual plan hearings, council strategy and development general management Kate Styles said yesterday the project was still viable, even with the reduction.
Mrs Styles said the extension was necessary for the future of the building.
Her views were backed by Cr Dave Cull, who has attracted criticism from opponents for changing his mind and supporting the extension.
A report by Dunedin Centre manager Savanna Dawson, approved by Mrs Styles, recommended "option 14" - a reduced version of the extension - should go ahead.
The report, to be considered by councillors at Monday's annual plan hearings committee, was a response to a peer review by Dr Diane Brand, of the Auckland University school of architecture and urban design.
When the review was released on Monday, Mrs Styles said staff would have to consider whether the extension was still viable with smaller extensions.
Yesterday, she said a decision had been made that it was.
The report said the smaller Harrop St extension would "successfully improve the general flow of the town hall complex".
Harrop St could still be used as a loading area, eliminating the need for a loading dock where the Metro Theatre was located.
"The view of the First Church spire is retained, and will be well appreciated from the new Harrop Court, and new exciting views will be provided from the upper levels of the new extension."
The report lists in a timeline that resource consent was "not applicable" for the new design.
The extensions fell within the current designation line of the building, "simplifying" resource consent procedures.
Hands off Harrop member, lawyer Lane Andersen, said last night that would be one of the issues the group would have to take to the Environment Court - something it intended to do.
