The council is talking with Mr Scott, his consulting engineer who designed the system, the company that built it and Mr Scott's consultant who ticked it off as having met its consent conditions.
Mr Scott said the infrastructure now belonged to the council after it had ticked it off as complying with its consent and he wanted the matter sorted out as soon as possible.
"It's not having a direct impact on anything (to do with the development) at this stage.
"I've asked the council to deal with it as quickly as possible, though," Mr Scott said.
"The council oversaw (the infrastructure construction) and signed it off, so as far as I'm concerned everything was done the correct way."
Mr Weston said the investigation could take months to establish what went wrong.
"We've engaged a consultant to assist in establishing the modes of failure (of the parts of the systems)," Mr Weston said.
It would also look at whether the low pH (acidic) ground water was an issue and if the construction work was carried out adequately.
"We are trying to establish who is at fault, who did what. Until we are sure who did what we can't determinate what our response will be."
The best-case scenario would be that the repair bill was picked up by whoever was found liable, but the worst could be ratepayers spending several million dollars on it.
Mr Weston said such problems had not occurred on any of the many other developments in the district.
Mr Jones said in Parliament last week that the infrastructure "collapse" had put a potential $20 million liability on ratepayers, but Mr Weston said that figure was way off the mark. However, he did say it could cost several million to sort out.
But Mr Jones said regardless of the exact amount, something had gone wrong that left ratepayers potentially liable for millions of dollars of costs and an investigation was needed.
"Given the problems in the Kaipara, we don't want Whangarei ratepayers left with a big bill over a system that has gone wrong," he said.