Discount supermarket chain Aldi is accelerating a trial of a more modern prototype store as it fine-tunes its format and store interiors for the first time in the 14 years since the German retailer arrived in Australia.

After testing four stores in the marketplace for the past six months, as part of a modernisation of the brand, Aldi is about to roll out another four stores with the new format.

But Aldi executives say it will be some time before final decisions are made about whether to bring the new formats right through the wider Aldi network, which now sits at 382 stores on the eastern seaboard, producing annual revenues of $6 billion-plus.

The company is also being careful about future timelines for any substantial rollout. Initial feedback from its customer base raised concerns that the brighter and more modern interiors brought an automatic assumption that prices would have to rise.