The project was a "bad idea economically", would be detrimental to a high-value conservation area and would probably be scuppered by ministry officials assessing the proposal, Mr Hackwell said yesterday, when contacted by the Otago Daily Times.
Forest and Bird owned land in the Hollyford Valley and would oppose the project, should it ever get to the resource consent stage, Mr Hackwell said.
"I look forward to the ministries' analysis. I hope they have a really good look at it and the costs. There are files and files and files sitting in Wellington where this has come up before and economics have killed it," Mr Hackwell said yesterday.
Economic Development Minister Gerry Brownlee this week said significant support was needed from New Zealanders before he would present a case to Cabinet, although he personally supported the idea.
Mr Brownlee has asked the ministries of economic development and tourism to report back to him on a study commissioned by Scenic Group director Earl Hagaman last year suggesting a 108km coastal route between Martyr Homestead (Haast) and Gunn's camp (Hollyford) would cost between $200 million and $300 million.
While Mr Brownlee said the cost appeared "on the light side" and the project faced financial constraints, he shared Mr Hagaman's view it would be good for the tourism industry and would open up a remote area to people who would not otherwise be able to go there.
He has suggested a public-private partnership, and strong support from consenting authorities would be needed.
A Haast-Hollyford road was first mooted over a century ago.
Former Prime Minister Sir Keith Holyoake championed the idea in 1965 when he opened the Haast Pass road to Wanaka.
Mr Hackwell said the road would also destroy some of the country's most valuable tourism infrastructure and conservation estate.
The taxpayer would subsidise the costs of constructing and maintaining a road that would benefit West Coast and Milford Sound hotel owners and road builders at the expense of tourist businesses in Makarora, Lake Hawea, Wanaka and Queenstown, he said.
"The road itself won't generate any more tourists. It will divert the traffic . . . the benefits to Mr Hagaman and a few people at Milford would be paid for by others," said Mr Hackwell, an environmentalist for 40 years.
Mr Hackwell also said it was "shallow" and "pathetic" to argue the road would open up an area isolated from all but the young and fit.
"We should put a gondola all the way up Mt Cook, too," he countered.
The Department of Conservation had done a lot of work opening up the front country to all people, while the tourism industry was already obtaining a huge amount of value from those fit enough to walk or rich enough to hire a helicopter into remote areas, he said.
Mr Hagaman said this week he expected opposition and "if greenies felt that strongly, they should go live in a cave".
Mr Hackwell said it was not about living in caves or denying access, but about having a spectrum of activities.
"We want there to be a healthy tourism industry. We are really pleased there's a massive tourism industry in the conservation estate, generating a massive economic contribution."
