Ofcom's auction of 2.3GHz and 3.4GHz spectrum, which could be used to meet growing mobile broadband demand, could take place next year.
The media regulator is inviting industry stakeholders to comment on proposals for the release, which is being lined up for late 2015, or early 2016 at the latest.
Ofcom has not specified any particular use for the spectrum, but the UK's mobile operators are expected to bid.
With an increasing number of consumers and businesses using 3G and 4G services - and demand for data rising all the time - the spectrum could offer valuable additional network capacity for the likes of EE, Vodafone, O2 and Three.
Fixed-line operators could also bid, as BT did successfully in the 4G auction staged in spring 2013.
The 2.3GHz band is currently being used for 4G mobile broadband in ten countries outside of Europe, including China, India and Australia. The 3.4GHz band is used in six countries at present, including the UK, Canada and Spain.
Ofcom is proposing to hold an auction for a total of 190MHz of spectrum in the two bands. This is equivalent to around three-quarters of the airwaves released through the 2013 auction.
At present, the spectrum is in use by the Ministry of Defence, but the government is eager to free up public sector spectrum for civil uses.
Ofcom is proposing to auction the spectrum in 38 lots of 5MHz, with bidders able to request a minimum bid of four lots per band.
Philip Marnick, Spectrum Group Director at Ofcom, said the announcement marks "an important step" in ensuring the UK has sufficient spectrum to support its wireless economy.
"It comes in response to the fast pace of change and innovation taking place in the communications sector, which is placing increased demands on how spectrum is used by all industries," he stated.
"One important way of meeting this demand is making new spectrum available and its use as flexible as possible."