Airbus is further hiking the maximum take-off weight of the A330, raising it to 242t, and will offer a higher fuel capacity option for the larger A330-300 variant.
The airframer had previously disclosed plans to increase the twinjet's take-off weight to 240t.
Airbus's latest enhancements will extend the range of the A330-300 by 500nm (930km) over the 235t model, and by 350nm for the 238t A330-200 at full passenger load.
It will give operators of the -300 the option of activating the centre wing fuel tank, a standard feature on the longer-range -200 but one which has remained unused on the larger aircraft.
This will increase the -300's fuel capacity from 97,500 litres to more than 139,000 litres. The modification will include tank inerting.
Airbus hopes the improvements will extend the A330-300's range to 6,100nm by 2015, enabling it to perform westbound flights from south-east Asia to Europe.
A330 programme chief Patrick Piedrafita says the airframer has "taken it as our duty" to maximise the capability of the twinjet.
Airbus took gross orders for 76 of the type over the first 10 months of this year, and delivered 80 - including six freighters - over the same period.
"We are currently delivering more A330s per month than ever before, and this is set to continue," adds Piedrafita.
Airbus's formal technical documentation for the A330 lists 21 weight variants for both the -200 and -300. The new weight increase and fuel-capacity improvements will become available to carriers in 2015.
The airframer is aiming to achieve the enhancements by refining the A330's aerodynamics - shortening flap-track fairings and reshaping inner slats - and capitalising on the aircraft's load-alleviation function. The aircraft will also undergo partial wing and fuselage reinforcement.
Airbus expects to reduce the -300's fuel burn by 2%, half of which will derive from the aerodynamic tweaks and the rest from higher engine efficiency.
No customer for the 242t variant has been disclosed but lessor CIT had signed up to take the 240t version shortly after it was unveiled in July this year.