KiwiRail has been warned that current government handouts cannot continue - as new spending in transport bypasses Auckland and goes to regional roading.

And SuperGold cardholders should have certainty in the scheme after close to $41 million in extra funding over four years, the Government says.

Today's two-year $190.2 million funding package for KiwiRail has come with a warning, with Transport Minister Simon Bridges saying ongoing subsidies at that level are "unsustainable".

The new Budget spending takes total investment in the company since 2010 to $1.4 billion.

"KiwiRail has made good progress in increasing customer numbers, becoming more reliable and upgrading assets. However, the Government expects it to continue to improve its productivity and efficiency," Mr Bridges said.

"The Government is committed to a national rail network, but ongoing subsidies at this level are unsustainable.

"The funding is a two-year package to help KiwiRail make further gains so future government support can be reduced."

The boost for the SuperGold card scheme comes after it has been put under pressure because of the growth in cardholders and trips.

New Zealand First Winston Peters has campaigned on what he says is the Government's desire to reduce the benefits and cover of the SuperGold card, which gives free off-peak travel to those over 65.

"The Government supports increasing the mobility of SuperGold cardholders. That's why we're providing $40.9 million of additional funding to provide certainty for more than 670,000 cardholders who made 12.6 million trips last year," Mr Bridges said.

Up to $115 million of new capital funding over four years will miss out Auckland and go to previously announced roading projects in Gisborne, Marlborough and Taranaki. They are the Motu Bridge replacement, Opawa Bridge replacement, Awakino Tunnel bypass and Mt Messenger bypass.

The $190.2 injection into KiwiRail has been dubbed a "kiwi fail" by the Taxpayers' Union.

Executive director of the lobby group, Jordan Williams, said the Government has written off and spent $3.4 billion on the national rail operator since it was elected in 2008 and its plan to get KiwiRail standing on its own two feet has failed.

"Only politicians would throw good money after bad trying to breathe life into a 19th century technology, when driverless cars and trucks are on the horizon."