Two passengers were ordered off a Wellington bus to get change for their $20 notes, only for the driver to leave them on the roadside, witnesses say.

NZ Bus, which operates the Go Wellington service, is investigating the driver's actions, which would appear to be at odds with the company's rules.

The incident took place on the no 11 bus, from the eastern suburbs into the city, in the early hours of Tuesday morning.

Passenger Laura Simpson said she saw two men board at Taranaki St, and try to pay with $20 notes. They were berated by the female driver.

She allowed both men to ride the bus for a few blocks until it stopped near a Z service station. She then told them to go inside and get change.

One of the men protested, but both eventually stepped off the bus. At that point, the driver took off without them, Simpson said.

She claimed the driver also laughed as the men ran across the road. She filed an official complaint after the incident.

But another passenger, David MacKenzie, said the driver did not laugh.

His version of events was otherwise similar to Simpson's, but he said he sympathised with the driver, who he believed had intended to wait for the men but changed her mind to avoid holding up the other passengers.

The driver informed the men the next bus was only 15 minutes away before she drove off, MacKenzie said.

"She possibly should have stayed, but I can see why she didn't.

"It's public transport. There's a balance between customer service and the driver's responsibilities."

MacKenzie, who is a regular on the no 11, said one of the men had tried to pay with a $20 note on several previous occasions, and had been asked not to by the driver.

"She's normally a very friendly driver, but she does get annoyed with the $20 thing."

NZ Bus southern region chief operating officer Tonia Haskell confirmed a complaint had been laid over the incident, and that an investigation was under way.

She apologised to those affected, saying the company wanted passengers to have "positive bus experiences".

Its policy was to accept big notes and try to find change during the journey, she said.

"We do encourage passengers to use the Snapper card, or bring small change, as it is not safe for our drivers to carry large amounts of cash."

After news of the story broke on Stuff, more Wellington passengers come forward with similar complaints, though most did not want to be named.

One said she was "rudely" prevented from boarding a bus in Willis St because she had only a $20 note. "He said, 'No, I don't have change. You can't get on this bus'. I was actually on my way to a job interview, but he refused to let me on.

"This makes me very, very resentful of the bullying and power-trip cultures exhibited by a minority of bus drivers."

A Greater Wellington Regional Council spokeswoman confirmed it had received feedback about "the alleged behaviour of a driver". "We'll need to wait for NZ Bus to investigate but, if the allegations are correct, that behaviour is unacceptable and we would expect NZ Bus to take necessary action."

DRIVERS BEHAVING BADLY

- A mother driving through Hataitai in April claimed a Valley Flyer bus coming the other way shunted past her car then took off. She found the bus driver shortly afterwards, around the corner, having a cigarette.

- In March, blind woman Megan Johnston was left in tears after a Go Wellington driver refused to give her a discount because he thought she was faking her blindness. She had shown him her blind person's pass.

- Also in March, Ceri Jones of Island Bay, who was pregnant with twins, was told she could not get on a Go Wellington bus with her 2-year-old daughter unless she folded up her pram. It came a day after rules were changed to allow unfolded prams on buses.

- Were you on the bus? Contact news@dompost.co.nz