Victorian travellers are still chasing refunds from discount carrier AirAsia X a month after having their travel plans disrupted over the Christmas and New Year holiday period.

The carrier, based in Indonesia, sold tickets for direct flights between Melbourne and Bali late last year despite not having official permission to fly the route.

Hundreds of passengers were forced to take flights via Kuala Lumpur instead.

Tom Godfrey, a spokesman for consumer group Choice, described it as "misleading conduct" by AirAsia X.

Pascale Young and Vasko Vancev were excited about their New Year's Eve trip to Bali.

They had booked a direct flight that would have landed a day before they were due to meet up with friends to ring in 2015.

But just days before they were due to fly out, they received an email from AirAsia X saying their flight had to be re-routed through the Malaysian capital.

"I was at a loss. I thought it's just ridiculous that we now have to travel for 14 hours what was originally going to be a five-and-a-half hour trip," Mr Vancev said.

"When we got there we were so tired we couldn't even be bothered to even go out and have a drink [for New Year's Eve]. We just had to go to the hotel and sleep," Ms Pascale said.

Rebecca Diehm of Geelong said she had a "very frustrating experience" dealing with the company.

"I was due to fly out to Bali on Boxing Day and received a text message on Christmas Day telling me the flight was delayed and that it would be redirected through Kuala Lumpur," she said.

Her trip proceeded but she later found out her flight home had been cancelled.

There were no contact details and an email message told her not to expect a response for up to five days.

"So I was just stranded in Bali basically. I had to find my own way home," she said.

She booked another airline home.

'Frustrating experience'

After talking to friends and other travellers, Vasko Vancev and Pascale Young allegedly discovered that the company had been aware of the problem well before their flight.

"So all this time AirAsia X knew that the flights weren't going to go ahead and they waited until three days before our flight to let us know," Ms Young said.

"They were actually selling a product they never really had," Mr Vancev said.

Their return flight was cancelled and they had to scramble to find alternative flights on another carrier.

"It's like they intentionally chose to give us very short notice," Mr Vancev said.

"They really cornered us - because we didn't have a choice."

The couple lost their first night's accommodation and had to stay an extra two days in Bali waiting to get on another airline.

The company has processed their refund application, but it is not clear exactly how much money they will get back.

Choice advised travellers to demand that the company pay additional costs, like accommodation.

"AirAsia X has been caught out advertising and selling flights to a route that it didn't have permission to fly," Mr Godfrey said.

"This is very poor form from Air Asia and clearly consumers should seek a remedy."

Airline denies it misled customers

The ABC sought a response from AirAsia X, which is based in Jakarta.

"Indonesia AirAsia X denies it misled customers," the company said via email.

"It is permissible for airlines to advertise and sell tickets subject to gaining regulatory approvals on a route.

"AirAsia clearly stated that this service was subject to gaining these approvals."

But few passengers seem to have been aware of that proviso.

Mr Vancev said there was nothing in the original booking confirmation or in subsequent communications from the company to indicate the route had not been approved.

AirAsia X insisted that the changes were for "commercial reasons", he said.

"When I called to find out why our flight was changed, they didn't tell me anything about the flight path pending approval."

Australia's Civil Aviation Safety Authority (CASA) was still assessing AirAsia X's suitability to fly the route.

In a statement, CASA said "it is an offence under the civil aviation safety regulations for a person to represent that they are willing to conduct a flight if they do not hold the necessary authorisation for that flight".

"However, advertisements and offers for flights that have not been authorised by CASA, but which contain a notice indicating that the flights are subject to expected regulatory approval, may not be in breach of this regulation."

AirAsia X said it would start direct flights as soon as the regulatory process was completed.

But that was little comfort for customers caught up in the incident.

Asked if they would fly with AirAsia X again, Ms Diehm said "definitely not" and Mr Vancev said "no way".

"I would never recommend anyone to fly with AirAsia," Ms Young said.