An Opel Astra GTC variant powered by a new 1.6-litre turbo petrol engine promising more torque and improved efficiency is set to arrive in Australia next month.

Following the engine's debut in the Opel Cascada, Opel has announced the all-new 1.6-litre four-cylinder SIDI (spark ignition direct injection) Turbo engine will now power the front wheels of the three-door Opel Astra GTC hatchback.

2Opel 1.6 SIDI Turbo2

Performance of the 1.6 SIDI Turbo-powered GTC is down slightly from the existing $34,990 GTC Sport model, however, with its 0-100km/h time of 8.6 seconds and a 219km/h top speed coming up just short of the old car's 8.3-second and 220km/h ability.

Opel Australia’s Michelle Lang told CarAdvice that Opel Astra GTC Sport models powered by the new 1.6-litre engine were expected to start arriving in mid July, but would not confirm to what degree prices would be affected as a consequence of the update.

The new engine was initially revealed in April, along with plans for a new eight-speed automatic transmission.