Saving Springfield president Robert Lee said the council's basis for the need for the sport and recreation precinct was a deficit in playing hours on Rotorua's sports fields.
"That is the thrust of the council's argument."
The group had obtained a copy of an August 2018 report to the council that suggested investment of about $2m on Rotorua's sports fields would result in a surplus of about 25 to 35 playing hours a week, he said.
"Councillors haven't had access to that report [but] right there is the whole justification for repurposing the Springfield golf course torpedoed.
The report, called "Sports Field Construction Quality Assessment" was done by Sports Surface Design and Management for the council.
Lee said the information needed to be discussed at the council's Strategy, Policy and Finance Committee as the council had decided not to defer discussion of the future of the golf course.
"It's disappointing it wasn't even on the agenda [at the last meeting]. This goes absolutely contrary to the council's decision.
"The Strategy, Policy and Finance Committee is now obligated, and the chief executive [Geoff Williams] is obligated to carry out decisions made by the council.
"They cannot just disregard or ignore the decision of the council. It's very serious and undemocratic conduct at that point."
He said his group wanted a "swift decision" on the future of the golf course, ahead of its lease expiring in 2027.
"We don't want this hanging over our heads."
He said he wanted to remind the council Saving Springfield had the "weight of the community" on its side.
A council spokeswoman said the report was a "desktop analysis and the costings are generic and based on assumptions, not actual analysis of the fields".
"That report also recommended that due to features such as ground conditions limiting use, poor sites, ex-landfill histories etcetera that a full feasibility investigation of fields should be carried out prior to committing to any major capital investment."
She said the council had subsequently commissioned a more detailed investigation in September 2020 which focused on Neil Hunt Park and Puarenga Park – something she described as "two poor condition sports parks".
"This report concluded that capital investment would provide negligible extra winter playing time at both parks but playing experience at Neil Hunt Park could be improved through investment into a sand carpet surface, similar to what is used at the Stadium.
"However, the underlying ground conditions (sawdust) would be a risk to this type of infrastructure."
The 2020 report had also identified increased operational maintenance work to improve playing surface quality and the council was working on those, she said.
Council community wellbeing deputy chief executive Jocelyn Mikaere said there was a significant amount of work still to be done to ensure elected members and the wider community could "fully appreciate and make an informed decision" about the future of Springfield golf course.
"We believe we can complete that work and carry out consultation with the community well ahead of the lease expiry.
"It's very important that we have the full, up-to-date picture and that the whole community has the opportunity to have a voice in this conversation before any decisions are made."
The story so far
The council announced its vision for the Westbrook Sport and Recreation Precinct in March last year.
That proposal would incorporate Westbrook Reserve, Ray Boord Park, Smallbone Park, Rotorua International Stadium, Westbrook netball courts and the Springfield Golf Course.
At the time, the council said Rotorua's sports grounds and facilities were insufficient and incapable of coping with future demand.
In March this year, the proposal appeared again as part of documentation for the council's draft 2021-2031 Long-term Plan, as part of the 10-year capital expenditure programme.