"The Christchurch City Council decision to proceed has not required a contribution from any other council, so that says to me the city council has agreed to fund the full $683m," Riach said.
"[They] agreed to fund and proceed without having asked for any support from other territorial authorities.
"It could come to other councils in the future and seek contributions to lessen their own costs, but as far as I can tell the decision to proceed has been made regardless of any of that."
Whether the city council will still ask its neighbours is yet to be determined, but finding options to produce any additional funding that doesn't lump it all on its own ratepayers will be on the city council agenda.
One solution is to turn other council's ratepayers into spades to dig themselves out the financial hole.
Speaking at the city council's meeting, former city councillor Helen Broughton said there needed to be a targeted rate across other councils in Canterbury to help pay the extra $150 million needed for the stadium.
But stating an idea does not simply make it happen, and even if the city council does eventually ask its neighbours for financial assistance, it doesn't mean it will receive it.
Riach said if any request did eventuate it would require public consultation before any decision was made.
"If other councils like Ashburton were to be asked in the future, that request would have to go into our planning processes and involve consultation with our community."
Ashburton has just adopted its 2022-23 Annual Plan and won't be preparing the next Annual Plan for consultation until around March, so theoretically if a request was made Riach said that would presumably be the earliest it could discuss it with the community.
Selwyn Mayor Sam Broughton maintains that while he was open to any discussion there has been no request for it to take place yet.
"Selwyn's position remains that we are open to considering any request for funding for the stadium, but no formal request has been received so far," Broughton said.
"Any contribution from Selwyn would have to be subject to consultation with our community – but this needs to be a Canterbury-wide conversation. We would expect that a discussion about economic and other impacts across the region would be part of that process."
