The organiser of a commuter train crowdfunding campaign says Environment Canterbury staff "rubbished" his plan.
Tane Apanui is fundraising to buy second-hand passenger trains from Auckland, hoping to start a private rail service between Selwyn, Waimakariri and the Christchurch central city.
He estimated the Dash Rail plan could be carried out for $1.8 million - significantly cheaper than the $8.2 million estimate in an ECan report in 2014.
He met with ECan staff last month to discuss his plan, but said they rubbished it and were "condescending and negative".
"They told me it's not possible because you can't change the bus timetables, which is one of the most idiotic and unprofessional things I've heard in a professional meeting," he said.
But ECan senior manager public transport Stewart Gibbon said that was not the case.
"Any new rail service using existing rail lines, would require additional bus services to connect customers to their final destinations. This is not a reason not to endorse a given proposal, but must be factored into any financial considerations," he said.
He said that when the additional costs were factored in, the total cost of a rail scheme remained "at a level that is deemed to be unacceptable".
"A robust discussion was had between all the participants and a number of items within [Mr Apanui's] proposal were challenged and discussed in detail. In my opinion, those that were present were professional and treated Mr Apanui respectfully," he said.
ECan chairman David Bedford said the information provided by Mr Apanui was being reviewed, which was likely to take a few weeks.
"The viability of a rail service for Greater Christchurch has been considered several times over recent years. In short, the cost has been too great to support the projected patronage."
Mr Apanui tried to raise the money needed through a crowdfunding campaign, but was unsuccessful.
People had pledged $86,455 to the campaign before it closed on Sunday, but that money will be refunded because it failed to reach the target.
But he said the campaign had drawn a lot of interest from private companies, and he was hopeful a business partnership could be formed to get the plan off the ground.
"I don't see it as a failure at all, because the public support and interest in this has been really strong," he said.
He has already held meetings with several organisations this month, including Ara Institute of Canterbury and Ngai Tahu, hoping to involve them in a partnership.
Ara sustainability manager Shaun Bowler said no commitment to the plan had been made, but he was open to further meetings with Mr Apanui about it.
A survey of about 2400 staff and students at Ara last year found better public transport was something many of them wanted, he said.
He said more than 1000 staff and 18,000 students were based at Ara, and the location of the proposed station on Moorhouse Ave would be convenient for them.
"In principle, we support anything that gives people more choice and provides more sustainable transport options," he said.
Mr Apanui said the project was time-sensitive because it depended on being able to purchase the secondhand trains from KiwiRail, which he said overseas buyers were now interested in.