Friends of the Botanic Garden president Frank Buddingh said the decision could make it difficult for the organisation to raise funds for the garden, as people wanted a clear plan to back, but that now was not available.
Mr Buddingh, who attended the council meeting where the decision was made, also said it was clear "a number of councillors were not quite up to date and informed" on the issue when they made the decision.
On Monday, the council voted not to go ahead with a plan to realign Lovelock Ave, part of a redevelopment plan at the Dunedin Botanic Garden, an issue Mayor Dave Cull singled out for review shortly after he was elected last month.
Lovelock Environment Society secretary Dr Antony Wood, who has opposed the plan as it has gone through resource consent and council processes, said the council appeared to be responding to calls during the elections for it to heed public opinion.
"I hope that will be the end of it. It's been very distressing," he said.
"Citizens found themselves being opposed by council staff."He said there had not been "proper" consultation in the early stages of the project, but that had finally occurred with Monday's decision.
But Mr Buddingh said the council had "let us down a bit as a partner".
The friends had a long-standing history of helping fund projects, but the decision meant "some form of delay" in this case.
Some of the more vocal opponents of the realignment had also been members of his organisation, and he hoped what he described as "negative energy" could be turned into something more positive for the future of the garden.
Dunedin Amenities Society president Mick Field yesterday described the decision as "a triumph for politics, rather than progress".
Mr Field, who worked on aspects of the project during planning, described the council's decision as "sad".
He warned Dunedin could end up "with egg on its face" if people attending the 2013 Global Botanic Garden Conference recently attracted to the city found crumbling infrastructure at the garden when they came.
Council community and recreation services manager Mick Reece said the people who worked for years on the project were disappointed.
He was concerned some might have got the idea staff had not applied the necessary level of rigour to the project, and there were "connotations we got it wrong".
That was not the case; rather, there were "social and political reasons it wasn't acceptable at this time".
Mr Reece said if councillors felt the realignment was unacceptable, staff would work on the next best plan, which would go before the council in December.
Dunedin Botanic Garden development plan
History:
*Started as an exercise for garden staff in 2004.
*Plans physical appearance of garden for 20-30 years.
*Presented to Friends of the Botanic Garden to confirm support, then to council for approval.
*Launched by Governor-General Anand Satyanand in October 2006.
The plan
* Realign Lovelock Ave to unlock full potential of upper garden, address threats to pedestrian safety, improve security, reduce garden and road maintenance. Council voted against this option.
* Relocate propagation/administration buildings to create new gateway to garden, free up land, remove unsightly storage facilities and work sites, establish suite of purpose-built buildings.
* Develop and complete series of destination features in middle area of garden to link upper and lower gardens, draw people into centre of garden (includes Mediterranean Garden under construction).
* Complete series of projects in lower garden to finish work started 10 years ago including entranceway project, Otaru Teien, Clive Lister garden and recently completed rose garden entranceway.
Cost: $6.5 million
