Public Transport Victoria (PTV) has refused to defend the actions of ticket inspectors who took hold of a woman's mobile phone.

High school teacher Rob Corr told ABC Radio Melbourne's Jon Faine he saw authorised officers (AOs) look through the woman's phone while asking her who she banked with.

They then asked her to log in to her banking app in order to prove her identity, Mr Corr said.

PTV chief executive Jeroen Weimar agreed with Faine's assertion that such behaviour was "totally inappropriate".

Mr Weimar said PTV had investigated the incident and AOs were told that they "should never touch, use or access people's information".

"Under no circumstances would an AO be taking somebody's phone, holding somebody's phone or trying to get into any of their applications or personal data," he said.

"I would never defend that."

Ticket inspectors 'pushy'

Mr Corr was walking with his wife past RMIT University, just outside the free tram zone, when he heard the AOs asking the woman who she banked with.

RMIT is one stop beyond Melbourne's free tram zone. ( 774 ABC Melbourne: Simon Leo Brown )

He said the AOs became "pushy" when he questioned them, claiming Mr Corr could not listen to their conversation with the woman because of the Privacy Act.

Mr Corr, who is also a lawyer, said the Privacy Act had no relevance to the situation.

"I was really worried that they didn't want people hearing what they were saying to her," he said.

He said the woman "clearly didn't speak much English" and had a friend interpreting for her.

"She was really worried that she would lose her visa," Mr Corr said.

"She obviously thought she was dealing with the police and it was a really serious matter."

Not standard procedure

Mr Corr said another AO told his wife that they were familiar with where to find user information in the banking app.

"Which made it to me sound like they did this on a regular basis, that this was almost their standard procedure," he said.

Listeners responded to Mr Corr's story with accounts of passengers being asked to log into Facebook to prove their identity.

Mr Weimar said AOs were entitled to ask someone travelling without a valid myki to prove their name and address, but it was up to the passenger what they provided as proof.

He said complaints about AOs had dropped by 60 per cent since the Government scrapped on-the-spot penalty fares.

"We check around 10 million tickets a year through the authorised officers," he said.

"They are doing a very difficult job on the whole very well."