A pair of large scrub fires alongside a northern Waikato railway line, are being fought today by a huge fire services contingent including multiple crews and helicopters.
The scrub fires are located in the small town of Pōkeno and further down the line at Meremere, about 4km apart.
Auckland city fire assistant area commander Barry Fox said they suspected the fires may have been caused by a faulty train, either by sparks or leaking fuel.
"We're not 100 per cent sure but we're pretty confident they're not suspicious looking fires," Fox said.
"We have some intel to indicated that it might be something to do with a train with a defective wheel, or something to do with the brakes, but that's not been confirmed.
"Dry fuel or scrub along the tracks, it just seems to tie together but we haven't had anything confirmed."
Fox said two helicopters were dropping water from the air, and there were 12 fire crews fighting the fires from the ground.
The Meremere fire was about 1km in length by 50 metres wide, and the Pōkeno blaze was around 400m by 50m.
Fox said both scrub fires were now under control, and there were no reports on people being injured.
"We're in a transition phase at the moment, we're moving crews out and scaling things down now," Fox said.