Priced from $35,600, the new A-Class will compete directly with BMW's new 1 Series, which currently kicks off at $36,900.
The A-Class will also go up against Audi's A3, and while local pricing for the new model is still to be announced, the current range begins at $40,500.
The new A-Class will debut with three petrol engines and one diesel, starting with the A 180 and topping out with the flagship A 250 - at least until the hot A 45 AMG arrives.
The A 180 is driven by a 1.6 litre turbocharged and direct-injected four-cylinder petrol engine, delivering 90kW and 200Nm of torque. Merc promises fuel consumption figures of 5.8 l/100km.
The mid-spec A 200 variants - priced at $40,000 and expected to be the volume sellers - are available in petrol and diesel form.
For the petrol A 200, power is provided by a more powerful version of the A 180's engine, listed at 115kW and 250Nm. The 1.8 litre diesel model produces 100kW and 300Nm.
Fuel consumption in the petrol version is rated at 6.1 l/100km, while the diesel model returns 4.6 l/100km.
The range-topping $49,900 A 250 will draw power from a 2.0 litre turbocharged petrol engine, producing 155kW and 350Nm of torque.
The A 250's also gets an AMG-developed front axle, along with a four-link rear axle. Various suspension settings can be optioned, including optional sports suspension with Direct-Steer.
All three models will be sold exclusively with a seven-speed dual-clutch automatic transmission.
The entry-level A 180 gets 17-inch alloy wheels and automatic headlights, along with a 5.7 inch display, USB and Bluetooth audio connectivity, reversing camera, and fabric/Artico combination interior trim.
With the A 200, there's 18-inch wheels and a twin exhaust, a chrome grille, leather steering wheel, sports highlights in the cabin and powered exterior mirrors.
The A 250 gets a standout styling package, including an AMG sports body kit with a 'diamond' grille pattern, 18-inch AMG alloy wheels and lowered AMG suspension, red brake calipers, bi-Xenon headlights, panoramic glass roof and tinted rear windows.
In the cabin are Artico-trimmed sports seats, an AMG steering wheel, carbon-look dash highlights, red vent rings, sports pedals and red seatbelts.
Standard safety features will include nine airbags, collision warning, fatigue detection and Mercedes' Pre-Safe system, designed to prepare the vehicle for an imminent collision.
- 2013 A 180 1.6 petrol - $35,600
- 2013 A 200 1.6 petrol - $40,900
- 2013 A 200 CDI 1.8 diesel - $40,900
- 2013 A 250 2.0 litre petrol - $49,900