Australian transit police are investigating a racist rant on a train in Melbourne in which passengers defended the victim.

Video taken by passengers of a 37-year-old woman swearing and making racist comments to a man of African appearance inside the train has made the rounds on the internet.

Several passengers defended the man and challenged the woman over her comments.

Officers who boarded the train at a north Melbourne station said the woman was 'intoxicated and behaving erratically', according to ABC.

Police assessing charges

"They made the assessment for the safety of people on the train that they needed to remove those people immediately," said Senior Sergeant Dearne Dummett.

"Unfortunately the train then left the station so they were not able to speak to anyone on the train."

Police have the woman's details and they say they will make an assessment about charges once they view the video footage.

"Hopefully the person involved will come forward. We can then speak to them and we can form an assessment and go from there" she added.