A prototype of the 2013 BMW Z4 has been spied undergoing testing in Europe ahead of the updated roadster’s Australian launch in approximately 12 months’ time.

BMW Australia says the upgraded Z4 is scheduled to arrive in local showrooms in the third quarter of next year following the start of production in Regensburg, Bavaria in March 2013.

The facelift will arrive in Australia a little more than four years after the second-generation ‘E89’ BMW Z4 was launched in May 2009, and roughly two years after BMW Australia turbocharged its entire Z4 line-up with the addition of the 2.0-litre four-cylinder engine in the sDrive20i and sDrive28i variants.

BMW Australia’s Piers Scott says the updated Z4 will carry over the existing powertrains and the line-up will remain similar, although the local brand is still deciding whether it will continue to offer both six-cylinder variants or drop the sDrive35i in favour of offering only the sportier and more popular sDrive35is.

The spy shots confirm visual changes will be kept to a minimum, headlined by the adoption of brighter ‘angel eye’ LED headlamps, relocation of the side indicators from the front fenders to the mirrors, and revisions to the tail-light graphics.

The front and rear bumpers may also get small updates before the new Z4 hits showrooms.

Inside, the 2013 Z4 will benefit from fresh trim materials and upholstery options and is also expected to features an upgraded infotainment system with a revised iDrive controller.

BMW has sold 72 Z4s in Australia so far this year, up 4.3 per cent compared with 2011. The sDrive20i is priced from $76,900 while the flagship sDrive35is tops the range at $120,500.