Sydney is about to become the centre of a fare war between budget airlines after Malaysia's low-cost long-haul carrier AirAsia X confirmed it will begin flying between Kuala Lumpur and the harbour city from April.

Six weeks after Singapore Airline's new budget offshoot, Scoot, announced that it will begin daily services to Sydney from the middle of this year, AirAsia X today confirmed the worst-kept secret in aviation by declaring that it will fly daily between Sydney's Kingsford-Smith and KL from April 2.

To lure passengers on to its flights, the long-haul affiliate of Asia's largest budget airline AirAsia is offering one-way launch fares as low as AU$99 and premium seats for AU$499.

The arrival of both AirAsia X and Scoot at Australia's biggest airport will intensify pressure on Qantas's budget offshoot, Jetstar. AirAsia X already flies to the Gold Coast, Melbourne and Perth from Kuala Lumpur.

After ditching long-haul flights to Europe and India, AirAsia X is focusing its attention on destinations closer to its base in Malaysia such as Australia, China, Japan, South Korea and Taiwan. It has blamed the decision to drop routes to Europe and India on high jet fuel prices and weakening demand for air travel.

AirAsia X's chief executive Azran Osman-Rani said the lesson it had learned from flying to Europe and India was the need for high frequency flights and not to "stretch ourselves too thin".

AirAsia X -- in which Virgin's Richard Branson has a 10 percent stake -- has sought for the last four years to fly to Sydney at least twice a day but has been prevented from doing so by the Malaysian government, which has a cornerstone stake in Malaysia Airlines. The latter airline flies between Sydney and Kuala Lumpur.

However, AirAsia X has said the launch of Scoot has helped convince Malaysian regulators to allow it to service more routes. "This is something that we have been pushing very hard," Mr Osman-Rani said of AirAsia X's efforts to gain approval to fly to Sydney.

AirAsia X will fly an Airbus A330-300 wide-body aircraft on the Sydney-KL route which will be configured with 13 premium flat-bed seats and 365 economy seats.

"Australia is a key market for AirAsia X and the Sydney route has long been a priority due to strong demand from Sydneysiders who have been screaming out for more competition," Mr Osman-Rani said.

AirAsia X has four weekly flights to Paris and and six to London, the last of which will be on March 30 and March 31, respectively. Flights to Mumbai will cease on January 31 and to New Delhi on March 22. The airline has said it would offer passengers affected by the changes an alternative travel option at no extra cost.

Jetstar had been talking about launching long-haul flights to Europe when it takes delivery of its first Boeing 787 aircraft next year. But more recently its focus has shifted towards north Asia, including Japan, where it will launch an affiliate on domestic routes later this year.

Long-haul routes have traditionally been the sole domain of premium airlines.