Speaking after the opening of the trail's first stage in Lumsden by Deputy Prime Minister Bill English on Saturday, Mr Tong said the event was a ''big milestone'' that would help win over its few remaining skeptics.
During his mayoral campaign last year he had received some negative feedback about the trail but, at the weekend's opening, many of the same people said they had changed their minds.
The opening of the New Zealand Cycle Trail Great Ride's first stage, an 80km stretch from Kingston to Mossburn, attracted an estimated 350 people to the Lumdsen Railway Station.
On its completion, the trail will run from Walter Peak up the Von River Valley to Mavora Lakes, and then through the rural Southland townships of Mossburn, Lumsden, Athol and Garston, finishing in Kingston.
The Southland District Council still needs resource consent for part of the second stage from Mossburn to Walter Peak. The prospect of a trail through the upper Oreti Valley, an area renowned for fly fishing, has drawn opposition from anglers.
A 2012 resource consent application by the council was declined on the basis of the trail's potential impact on the area, and submissions are now being accepted on a second application.
Mr Tong said landowner consents had been signed off and tender documents for building the trail were ready to go out once consent was granted.
It had taken since 2009 to get the first stage completed, and the trail's backers were determined to meet a December 2015 deadline for completing the whole trail.
About $4 million had been spent so far, and it would cost about the same again to finish it off, he said.
