Tiger Australia's managing director Shelley Roberts.

Tiger Australia's managing director Shelley Roberts.

Qantas and Virgin Blue's grip on one of the world's busiest routes between Sydney and Melbourne ended today with the entry of low-cost carrier Tiger Airways.

Tiger's first aircraft to fly the route was set to touchdown in Sydney at 2.45pm today, heralding the start of four flights a day service between Sydney's Kingsford Smith and Melbourne's Tullamarine airports and breaking the duopoly held between Qantas and Virgin since 2001.

The entry of the Ryanair wannabe of south-east Asia into Sydney poses the biggest challenge to Qantas's low-cost subsidiary, Jetstar, although Qantas and Virgin are expected to compete vigorously to maintain their market shares.

Offering one-way fares starting at $39 (including tax and charges), the Singapore Airline-backed Tiger has the lofty intention in the midst of the worst downturn in aviation of growing the market by attracting people who do not usually fly.

Tiger Australia's managing director, Shelley Roberts, said today that the carrier's strategy was about offering the lowest fares in the market.

Passengers have to pay for additional services such as baggage and meals.

"We have got ourselves into the false belief that there is space in Australia for only two airlines," Ms Roberts said. "We are about to grow the market on the world's third busiest route."

Tiger is aimed primarily at the leisure market because of the times it departs Sydney at 8.45am, 3.20pm, 6.20pm and 9.30pm.

With the launch of services between Sydney and Melbourne today, Tiger will fly 17 routes around the country using six 180-seat A320 aircraft. It will also begin a daily service between Sydney and Adelaide at the end of this month.

Its foray into the so-called golden triangle of Sydney-Melbourne-Brisbane comes just a day before the world's largest carrier, Delta Airline, begins daily services between Sydney and Los Angeles, taking to four the number of airlines flying the trans-Pacific.