Europe's Airbus has delivered its first A330neo jet to TAP Portugal as it seeks to trump US rival Boeing in the competitive battle at the lower end of the market for long-haul jets. 

The face-off between the A330neo and Boeing 787 pits two generations of jetliner against each other in one of the most crowded but potentially lucrative parts of the aircraft market.

The market is predicted to represent $1 trillion in sales over 20 years. 

The A330neo offers fuel savings through new engines from Rolls-Royce, though these have been delayed by industrial problems at the British supplier. 

Airbus planemaking chief Guillaume Faury said he expected Airbus to catch up on delayed A330neo deliveries by end-2019. 

Sales of the A330neo have also fallen short of expectations as Boeing places its 787, but Faury predicted these would pick up following the first delivery. 

"The A330neo will in my view get more traction when it is in service," he told reporters. 

One of the earliest and largest customers for the A330neo, leasing firm Avolon which financed the first TAP aircraft, said Airbus still needed to win more orders. 

"It is a soft order backlog. We would prefer if there were more airplanes sold to more customers - wouldn’t anybody?," Avolon's chief executive Domhnal Slattery told Reuters. 

"But the thing that is giving us comfort is that the replacement wave for the (earlier) A330-200 hasn’t really kicked in and it should kick in this year, next year and the year after," he added. 

Airbus recently won A330neo orders from Kuwait Airways and Delta Air Lines.

But Delta said it had deferred some deliveries of the newer A350 and industry sources say Kuwait had been given flexibility to delay or cancel A350s in return for its support.

The A330neo - sporting a newer cabin and larger engines than existing A330 long-haul jets - is the latest gambit in a battle between Airbus and Boeing over the fiercely contested 'middle of the market,' sitting between long-haul and medium-haul planes. 

Boeing is weighing proposals to develop a dedicated jet carrying 220-270 people in a development analysts say could damage the A330, the most profitable Airbus wide-body model. 

Airbus is attempting to close its jaws around the same part of the market through a combination of the 250-300-seat A330neo at the top end and the smaller A321neo underneath.

Boeing says it has won 65% of wide-body orders in the last five years. 

Airbus says the A330 won some 50% of orders contested against the 787 since the A330neo version was launched in 2014. Both firms select data to support marketing campaigns. 

The aircraft delivered to TAP Portugal yesterday is the 298-seat A330-900neo, the larger of two versions developed by Airbus and one that dominates the tally of 242 aircraft on order. 

Of these, 28 are officially earmarked for IranAir but Airbus says these will not be delivered any time soon due to renewed US sanctions, which apply to all jets using significant US parts.

The smaller A330-800neo took its first flight this month.