"We are horrified to think motorists would deliberately put themselves, and any passengers they may have, in such grave danger," said KiwiRail chief executive Jim Quinn.
"There is no journey so important that it can't wait a couple of minutes."
His warning comes as the Herald obtained information revealing the six most dangerous rail crossings, where three collisions have occurred at each in the past 10 years.
A further 31 crossings have had two crashes each.
That was out of 235 collisions at crossings between trains and road vehicles, and 34 involving pedestrians.
The most dangerous - with three collisions each - were at crossings in Hamilton, Auckland, Tauranga, Kawerau, Mt Maunganui and Ashhurst. Of the three at the Fruitvale Rd crossing in New Lynn, one was fatal.
Since the three, which happened between 2004 and 2006, a new half-arm barrier has been installed in the hope of improving safety.
Similar barriers have also been installed at Peachgrove Rd, Hamilton, and Bureta Rd, Tauranga, while new flashing lights and bells were installed in Hillcrest Rd, Ashhurst. Nothing has been done to improve safety at Matapihi Rd in Mt Maunganui which already has a half-arm barrier.
In Kawerau, where there were three collisions at State Highway 30 - two fatal - lights and signs were improved but half-arm barriers have not been installed. KiwiRail is now rethinking that decision, after acknowledging a growth in rail traffic at the crossing, to an average of 11 trains a day, from eight in 2006, compared with about 2450 road vehicles.
The traffic growth was not enough to justify half-arm barriers, Kiwirail said. It had a priority list of 78 crossings which meet its criteria for alarm upgrades.
Even so, a spokesman disclosed to the Herald that the government-owned company had decided to "re-assess this crossing for an upgrade".
He acknowledged that was because the crossing at Kawerau had been the scene of the greatest number of fatal or injury collisions in New Zealand over the past 10 years.
"We expect to have a view around what options exist to improve safety at this level crossing by the middle of the year."