Cathay Pacific A350-1000 arrives in Australia for the first commercial flight for Hong Kong-Melbourne route

The A350 is Airbus' chief rival to the Boeing 787 Dreamliner, but unlike the Dreamliner, which has a body composed primarily of carbon fibre, the A350 uses a combination of materials, including plastic reinforced by carbon fibre, along with titanium and aluminium alloys.

More than 70 per cent of the aircraft is made of lightweight materials, helping airlines save on fuel and reduce emissions.

Also like the Dreamliner, the A350 helps reduce jet-lag on long-haul flights, thanks to a lower cabin altitude than previous generation planes, meaning higher oxygen levels. Mood lighting and a quieter cabin is also designed to increase passenger comfort.

Rakesh Raicar, the airline's regional general manager for the south-west Pacific, said these more fuel-efficient aircraft offered benefits to both airlines and passengers, allowing more scheduled flights. That has been a factor that has seen the giants of the sky, the Airbus A380 and Boeing 747 jumbo jet, fall out of favour with airlines in recent years.

"Customers want frequency (and) flexibility, which means being able to choose between a number of flights," Mr Raicar said.

"This size aircraft allows us to operate three times a day from Melbourne and allows us to have flexibility of the timing of departure and arrival into Hong Kong, and also a choice of connections across our network. That's a bigger advantage than fitting everyone into one aircraft."

But it's a challenging time to be launching a larger capacity plane on a Hong Kong flight, with ongoing protests in the city seeing some travellers shying away from the destination.

Qantas last week cited low demand on its Hong Kong route as impacting its earnings to the tune of $25 million.

Cathay Pacific, as Hong Kong's own major airline, has seen a significant impact, with passengers numbers for September down 7.1 per cent year on year to 2.4 million.

Mr Raicar said one reason for the larger A350 launching in Australia was the continued demand from the country, pointing out that Sunday's return flight to Hong Kong of the new plane was full.

"Clearly it's a challenging time for us, and a challenging time for Hong Kong as well. That said … we've also seen a nice amount of resilience from the Australian market. All through this crisis period we've seen good load factors from Australia and we're very grateful for that.

"Compared to many other countries across the network, Australia is a bright spot for us right now. And that gives us the confidence to bring the A350-1000 into Melbourne, which is a key market for us."

The launch customer for the A350-1000, Qatar Airways, was set to be the first carrier to bring the plane to Australia, but the launch of the plane on the Doha-Sydney route has been delayed until mid-November.

See also: Airline review: Cathay Pacific premium economy on the Airbus A350

See also: Qantas' first redesigned A380 superjumbo takes off