Transport Minister Steven Joyce says what will keep smaller rail routes open is more custom.
Parliament has received petitions aimed at keeping the Auckland-Northland and Napier-Gisborne lines open.
Both routes are under review by KiwiRail because they are uneconomic; decisions on them due in the middle of next year.
Mr Joyce says while petitions are good, customers are better.
"The reason KiwiRail are taking significant time over the review," he says, "is to give them an opportunity to find the customers if those customers are available.
"I think that's the right approach, because you do want to try and use the rail link if you can."
KiwiRail is also reviewing the rail line from Masterton to Pahiatua.
The Green Party says the lines should be kept open, because they are key to the communities' economic futures, given that oil reserves are being depleted.
Transport spokesperson Gareth Hughes says roading and the trucking sector have been subsidised to a large extent and it's time for more investment in rail.
"Businesses want to use rail," Mr Hughes says, "but the fact is they've been under-invested and asset-stripped over decades."
He says there is plenty of money available to invest in rail but the Government is putting all its eggs in the motorway basket.
