SMARTphone users in the UK will have to wait until next year at the earliest to access the next generation of super-fast 4G mobile broadband internet connections.

Ofcom has unveiled plans for the largest-ever auction of airspace for mobile services, which will allow 98% of smartphone and tablet users to download data, such as music and films, at much faster speeds.

But the regulator's sale will not start until the end of the year with mobile operators unlikely to roll out services until the middle of 2013. However, once established it will mean coverage will improve for all types of mobile devices.

Consumer groups have welcomed the news, and have called on the communications regulator to ensure there are no more delays.

Bob Warner, chairman of the Communications Consumer Panel, said: "Rolling out mobile broadband to at least 98% of people will ensure those who have poor or non-existent mobile voice coverage will benefit too.

"Consumers in the UK have been waiting for some time for the benefits from 4G. We call on Ofcom and operators to deliver this without further delay."

The auction is expected to raise billions of pounds for Treasury coffers. The previous 3G sale pulled in £22.5bn from mobile companies.

Ofcom expects the process to start before the end of this year. Applications will be assessed before the bidding phase starts, likely to be in early 2013.

Eddie Murphy, telecoms analyst and founder of Priory Consulting, said there would be a feeling of deflation in the industry at the latest delay.

"But it's probably very important from Ofcom's point of view to get it right," he added.

Ofcom has reserved a minimum amount of spectrum in the auction for a fourth operator on top of the three big mobile firms – Vodafone, 02 owner Telefonica, and Orange and T-Mobile firm Everything Everywhere.

The auction will offer at least two spectrum bands – 800 MHz and 2.6 GHz. The lower 800 MHz band is ideal for widespread mobile coverage, while the higher frequency is good for delivering faster speeds.

The combination of low and high-frequency spectrum creates a potential for 4G mobile broadband services to be widely available across the UK, while offering capacity to cope with demand in urban areas.

Ofcom chief executive Ed Richards said: "The 4G auction is designed to deliver the maximum benefit to consumers.

"People will be able to surf the web, stream videos and download email attachments on their mobile device from almost every home in the UK."