"There was so much dirt and dust coming from behind it, and then it was almost like in slow-motion, like seeing a building being demolished.
"The first wagon came off the track and then the other ones flipped over it like dominos.
"The driver got out and was walking around and he seemed OK, it doesn't look like anyone has been injured."
Mr Stables said the main track was completely blocked.
"If you've ever stood there and seen a train roll over, it is unreal."
Kiwirail spokeswoman Julie Buchanan said five wagons derailed about 4pm.
"As a result of the incident, part of the train is blocking the Fisher Rd level crossing, and freight services on that section of the North Island Main Trunk line are going to be disrupted. KiwiRail is working to clear the site, and while it is too early to say what caused the derailment, we will be investigating."