Watch: Fuel tanker's near miss with train under KiwiRail review

A fuel tanker drove through lowered barrier arms at a railway crossing. Photo / Supplied

The harrowing moment a fuel tanker glides through lowered barrier arms at a Waikato railway crossing could have caused mass casualties, according to one safety official.

Footage shows a Linfox tanker drive over a crossing in Ngāruawāhia seconds before a freight train comes powering down the line - an incident which is now under review by KiwiRail.

TrackSafe spokeswoman Megan Drayton said the incident was incredibly unsafe.

"Flashing lights and barrier arms are there to protect people so to see someone deliberately driving around them is really shocking," Drayton said.

"I have never seen a fuel tanker drive around barrier arms."

The fallout could have been "catastrophic".

"If a tanker collides with a train travelling 80km/h there is potential for mass casualties."

The crossing is near a BP petrol station.

A KiwiRail spokesperson said it was notified of this incident by Linfox.

"We take safety very seriously and were pleased to hear that they acted quickly and proactively following the incident, including educating staff nationwide on rail safety."

KiwiRail was conducting a review of the incident, he said.

"It's important to always obey warning signs, alarms and signals at level crossings, and never cross if barrier arms are down."

Linfox has been contacted for comment.