Costs to repair the Napier-Gisborne line, currently closed from Wairoa to Gisborne, are around $4 million. It costs KiwiRail about $2.1 million a year to maintain the track infrastructure and a further $1 million year to run one to two train services a week.
Green Party transport spokesperson Julie Anne Genter said the comments would only serve to soften the blow for when the line was eventually closed.
"Less than a week ago John Key said the decision on the line would be up to KiwiRail. That's been followed by the New Zealand Transport Agency's latest funding round announcement which has no money flagged to repair the line.
"In the meantime, the KiwiRail website is saying the line is not viable. It says mothballing doesn't mean closure but it really does as we've seen with other regional lines."
She said the Government was "picking a winner for the future", which was to shift more freight on to road at a time when people wanted "greener and safer transport infrastructure".
"We think that's really short-sighted.
"The cost of rebuilding and maintaining the line is a tiny fraction of what the Government was currently spending on building new motorways.
"There are business who desperately want to use the line but there has been no analysis of the significant long-term benefits to the road network."
The KiwiRail website comments said it had spent considerable time canvassing local business about current and future opportunities.
It had taken a 10-year future look at the line. "We've also worked closely with the New Zealand Transport Agency to establish impacts on wider transport networks."
KiwiRail's communications manager Kimberley Brady said no decision had been made on the future of the Napier-Gisborne line but an announcement could be made in the next couple of weeks.
"We hope it will be made very soon."