The new-generation 2015 Opel Astra has been spotted undergoing testing at an engineering facility by CarAdvice's spy photographers in Europe.

Opel Astra 1

Our spies suggest the new-generation Astra hasn't hit the road as part of its real-world testing at this point, but the car spotted here is clearly a production prototype that gives us an idea of how the new model melds the swoopy hatchback shape of the current model with more sharply styled lines at the front and rear.

While heavily camouflaged, the new model's high-tech headlights cut a fine shape at the front of the car, and its bonnet is expected to sit higher than the existing model as a means of improving its pedestrian crash test rating. Other differences include the side mirrors, which have migrated from the A-pillar to sit on the front doors. Along with the repositioned mirrors, a larger rear roof-top spoiler should help the new model cut through the air more efficiently.

The new Astra is rumoured to drop as much as 100 kilograms over the current car which tipped the scales at between 1394 and 1525kg in five-door hatchback guise. The new model rides on the existing Delta II underpinnings and is expected to grow by about 60 millimetres in length to 4479mm, and while it is currently unclear if the wheelbase of the car has been stretched, it appears slightly longer between the wheels to us.

Opel Astra 4

Under the bonnet, General Motors' new efficient engine range including turbocharged three- and four-cylinder motors that will be offered across numerous models, including the Astra and the next-generation Cruze. The new engines are lighter and considerably more efficient than the current range of four-cylinder engines used, and a new six-speed dual-clutch automatic is expected to be offered on some variants.

No images of the car's interior have been forthcoming at this stage, though it is expected the new model will ditch the button-heavy layout of the current car (phew!) in favour of a new touch-screen media system and fresh controls for other functions.

Opel is expected to offer the same bodystyles as the current Astra range, including a five-door hatchback which will launch first, followed by a five-door station wagon and three-door hatchback that will be used as the basis for the next-generation GTC and OPC hot-hatch models.

As CarAdvice has previously reported, the Astra is set to make a return to the Australian arm of General Motors' small car line-up, and could be sold alongside the all-new Cruze from 2016. However, according to a company source, some Astra variants such as the current generation GTC and OPC hot-hatch may be sold much sooner.

Opel Astra 7

The new Astra may debut at the 2015 Geneva motor show in March, or possibly later in 2015 at the Frankfurt motor show.

Click the Photos tab above for more images of the new Opel Astra.