The man was kicked off the train about 1.20pm yesterday after being confronted by guards.
An onlooker, who filmed the incident on his mobile phone, said the man told guards the animal was to help with a medical condition.
He reportedly showed them a letter on his mobile phone to prove the dog was not a pet.
The video in the player above shows the man arguing he has approval for the dog and refusing to leave the train before the guards grab the man and drag him off the train.
The Public Transport Authority has defended the actions of guards.
A spokesman said footage of the incident had been reviewed and the PTA was satisfied transit officers had performed their duties appropriately.
“We have no concerns about the manner in which the man was removed,” he said.
“The rules around travel with assistance animals on the Transperth system are clear.
“Passengers travelling with assistance animals must carry a valid photo ID of the dog or have a suitably marked dog coat or harness that identifies it.”
The spokesman added that in this instance the man had failed to provide any of the required material and claims he was removed after he ‘became abusive.’
He was given a verbal caution for disorderly behaviour.
This article originally appeared on PerthNow.