"No cash accepted" signs are becoming an increasingly common sight in shops and eateries across Sweden as payments go digital and mobile.

But the pace at which cash is vanishing has authorities worried. A broad review of central bank legislation that's under way is now taking a special look at the situation, with an interim report due as early as the summer.

"If this development with cash disappearing happens too fast, it can be difficult to maintain the infrastructure" for handling cash, said Mats Dillen, the head of the parliamentary review. He declined to give more details on the types of proposals that could be included in the report.

Sweden is widely regarded as the most cashless society on the planet. Most of the country's bank branches have stopped handling cash; many shops, museums and restaurants now only accept plastic or mobile payments. But there's a downside, since many people, in particular the elderly, don't have access to the digital society.