A rail lobby group says it fears more line closures will follow the mothballing of the Taranaki-King Country rail line.
The line was closed by Kiwi Rail after 8km of railway sleepers at the northern end of the Taranaki to King Country line were damaged by a derailment on Monday.
KiwiRail chief executive Jim Quinn said repairing the line would cost up to $400,000, which he said would be too much as only one return train used the track a day.
"The amount of traffic using it at the moment doesn't justify continuing with repair work without a considered look at likely future freight volumes," he said.
"That doesn't mean we have decided to close the line."
The train that did use the line -- believed to be one transporting milk product from Fonterra farms in Taranaki to Tauranga -- will now be diverted hundreds of kilometres further, via Marton and the North Island Main Trunk Line.
"As a country we are supposed to be focused on improving the efficiency of freight and reducing our greenhouse gas emissions," Campaign for Better Transport spokesman Jon Reeves said.
"It doesn't make sense to delay the decision on reopening the line until next year."
Mr Reeves said he was fearful "that this could be the thin edge of the wedge, with more line closures to come".
He said the main reason the line only had one train a day using it was because the track is in such poor condition.
"It has been so run down over the last decade that trains are barely capable of using it. If the line was fixed to a suitable standard then freight and passengers could take advantage a direct link between Taranaki and the Waikato."
Mr Reeves said the line did need to be closed temporarily so repairs could be carried out, "but we would like to see a commitment from KiwiRail and the Government to reopening the line as soon as possible".
Rail and Maritime Transport Union (RMTU) general secretary Wayne Butson said last week he believed the decision not to repair the line was heavily influenced by government attitudes towards publicly-owned KiwiRail.
"The National Party said they would not sell rail in the first term of their government, but neglecting basic repair work on our rail network is running down this valuable asset."
