Following shots of the Astra cabriolet in March, spy photographers have captured the Opel Astra sedan undergoing testing near the Nurburgring in Germany, ahead of its anticipated unveiling later this year.

The test mule shown here is wearing some light camouflage on the grille and on the rear end, which shows that the new Astra sedan shares its basic styling features with the Astra hatch launched in locally in 2010. The rear-end design is expected to closely resemble that of the Buick Verano and Excelle GT models – Astra-based sedans that went on sale last year in the US and China, where sedans are favoured over hatchbacks.

In terms of engine range, the model should be offered with the same line-up of currently available powerplants. In Europe, petrol engine choices include a 1.4-litre unit delivering 74 kW, a 1.6 delivering 85 kW and a turbocharged 1.4 producing 103 kW. As for the diesel, there will be a 1.3-litre engine producing 70 kW as well as a 1.7-litre in power outputs of 81, 92 and 95 kW. The inclusion of the more powerful 1.6-litre turbocharged 132 kW petrol engine and 122 kW 2.0-litre diesel unit, have not been confirmed, but will surely be on the cards.

International reports suggest the Opel Astra sedan will be unveiled at the 2012 Paris motor show in September.