Since 2005, Mr Hyland and fellow "Old Caversham Rail Tunnel" advocate Jane Bruce, of Dunedin, have developed plans for the disused 865m tunnel to be re-surfaced and lighting installed to provide bicycle and pedestrian access between Caversham and Green Island.
Last month they launched a website, www.cavershamtunnel.org.nz, which has since received more than 300 hits.
About 150 people responded to a three-page online questionnaire about usage.
"We hope there is a ground swell and the site creates some interest.
It is almost a criminal waste to see a Victorian era tunnel sitting there disused.
The response has been encouraging and the majority of respondents think it's a brilliant idea," Mr Hyland said.
The tunnel would allow cyclists travelling from the centre of Dunedin to reach the Taieri area (via the nearby disused Chain Hills Tunnel) and recreational and commuter cyclists to access Green Island and Brighton over less hilly terrain, and with little exposure to high-volume traffic areas.
Initially, a tunnel with a gravel base would "get the project up and working" but long term a sealed surface with lighting (possibly activated by motion sensors) would mean more people could use the tunnel with less concern for personal safety, he said.
The pair first approached the Dunedin City Council in 2006, and were then told cost estimates for the project would be up to $300,000.
Subsequent correspondence with the council indicated estimates, which may have included the cost of a raised walkway, ventilation and lighting, would be significantly higher.
"We were astonished when I later heard they were $600,000 to $850,000," Mr Hyland said.
Infrastructure Services Committee chairman Andrew Noone said as the proposal was presented during this year's annual plan submissions, a report would be made later this year on the feasibility of re-opening the tunnel.
"We would have to consider the practicalities and cost would be a driver.
It's a wonderful asset but in its current form the tunnel is only being used for services.
The potential exists for it to be used in other ways, which is wonderful for the city but, as I say, it comes down to practicality and further investigation would be needed."
Cr Noone and council staff visited the tunnel in 2006.
"We walked 100m and no further with a gas monitor and it certainly was active. It indicated it was not good idea to stay in there for too long. Underfoot the floor was very wet and boggy.
"In its current form it's not a place [one] would want to go in running shoes."
Cr Noone said he and council representatives would meet Mr Hyland on August 21.
