The all-new Audi A3 Sportback has been revealed in the lead-up to its global debut at next week’s 2012 Paris motor show.

The five-door A3 Sportback becomes the second body style in Audi’s third-generation premium small car range, following the three-door variant that first appeared at the Geneva motor show around six months ago.

The new Audi A3 Sportback is essentially a more practical version of the three-door hatch, and also takes a generational step forward from the outgoing five-door.

Audi Australia will only offer the five-door A3 Sportback down under when the new model arrives in the second quarter of 2013, opting against the more compact three-door model.

At 4310mm long, 1780mm wide and 1425mm tall, the A3 Sportback is only slightly larger than the model it replaces, although riding on an entirely new platform with a 2636mm wheelbase – it’s 58mm longer between the wheels than before, as well as 35mm longer from axle to axle than the new three-door.

Audi says the extra length has created more legroom for rear-seat passengers, while headroom has also increased.

The 380-litre flat-floored boot is 10 litres larger than before, and expands to 1220 litres with the 60/40 split rear seats folded forward (up 120 litres over the old model).

Like the three-door, the Audi A3 Sportback will launch globally with one TDI diesel engine and two TFSI petrol units. Two more diesels and another petrol will be added to the line-up in the coming months. Direct injection, turbocharging, thermal management and stop-start systems combine to reduce fuel consumption by an average of 10 per cent compared with the previous model.

The new 2.0 TDI will be available in two tunes: one with 110kW of power and 320Nm of torque, the other with 135kW and 380Nm. Surprisingly, the more powerful tune is around six per cent more fuel efficient on the combined cycle, at 4.3 litres per 100km, as well as one second quicker from 0-100km/h (7.4secs).

A smaller 1.6 TDI will be even more economical at 3.8L/100km, yet its sprint time blows out to a less zippy 10.9 seconds.

The new 1.4 TFSI engine features an aluminium block and, at 107kg, is 21kg lighter than its predecessor. A 90kW/200Nm tune accelerates the A3 Sportback to triple figures in 9.3 seconds and uses 5.3L/100km combined.

A more powerful tune coming later produces 103kW and 250Nm, cutting its sprint time by nine-tenths. Audi’s innovative cylinder deactivation technology – which shuts off the second and third cylinders at low to medium speeds and while coasting – reduces fuel consumption by 11 per cent to 4.7L/100km.

Upping the power is the new 1.8 TFSI, which generates 132kW and 250Nm for a 0-100km/h sprint of 7.3 seconds and combined cycle fuel use of 5.6L/100km.

An entry-level 77kW/175Nm 1.2 TFSI will expand the line-up later with figures of 10.7secs and 4.9L/100km.

Adding further diversity to the powertrain range in 2013 will be the high-performance S3 and an 81kW TCNG e-gas variant (pictured below), before the A3 Sportback e-tron will introduce plug-in hybrid propulsion to the range in 2014.

The Australian launch line-up is expected to feature two petrol engines and two diesels in what Audi is calling a streamlined approach.

All engines will be paired with either a six-speed manual transmission or six- or seven-speed dual-clutch S tronic automatic gearboxes.

Audi A3 Sportbacks with up to 103kW send their power to the front wheels, while Audi’s quattro all-wheel drive system is available as on option for 1.8 TFSI and 2.0 TDI models.

High-grade Audi A3 Ambition variants feature Audi drive select, which allows the driver to switch between five dynamic vehicle set-ups – comfort, automatic, dynamic, individual and efficiency – each one with its own unique accelerator, power steering and (where applicable) S tronic characteristics.

The interior features a brand-new infotainment system with either a 5.8- or 7.0-inch retractable screen as the focal point. Highlights include voice control, 3D satellite navigation maps, Bluetooth connectivity and up to 60GB of storage capacity.

Also integrated into the infotainment package is Audi connect, which facilitates internet connectivity, Google Earth integration, online traffic information, and text-to-speech functionality for smartphone applications like Facebook and Twitter.

A number of driver assist systems also join the new Audi A3 Sportback line-up. Adaptive cruise control, side assist and active lane assist, traffic sign recognition, park assist with 360-degree display, and the Pre Sense low-speed automatic emergency braking system that operates at speeds below 30km/h, headline the list of standard and optional systems.

The A3 Sportback’s interiors are matched to the trim line, with the base ‘Attraction’ finished in black or titanium grey with cloth seats, ‘Ambition’ in black or black and silver with cloth, and the premium level ‘Ambiente’ adding the choice of pashmina beige and chestnut brown colours as well as cloth/synthetic leather seats. Milano leather, Pearl Nappa leather and Alcantara upholstery upgrades are available optionally.

The S line package bathes the cabin in black, and adds silver stitching and brushed aluminium details to match the sporty exterior enhancements.

The all-new Audi A3 Sportback will premiere in Paris on September 27.