UK mobile operators Vodafone and 3 have asked for permission to run 4G mobile services over the airwaves they use for existing mobile services.
Currently EE is the the only UK operator that can run 4G services over those parts of the radio spectrum.
Telecoms regulator Ofcom has started a public consultation exercise on the proposal that runs until 29 March.
Ofcom is currently running an auction to sell off unused airwaves that can support 4G services.
The two mobile operators want to be able to pipe futuristic 4G services over parts of the radio spectrum that, on their networks, are reserved for earlier generations of mobile technology.
Among other things, 4G promises to improve web browsing speeds while on the move and make a host of other mobile applications much more feasible.
EE is the only UK operator offering 4G and now rivals want Ofcom to let them use their existing spectrum for 4G services. In its consultation document, the regulator proposes to "liberalise" all parts of the radio spectrum used for those 2G and 3G services so they can be used to support 4G.
"This will meet a long standing objective to liberalise all mobile licences so that there are no regulatory barriers to the deployment of the latest available mobile technology," it said in a statement.
It later added that: "The only reason we allowed EE to use its existing spectrum for 4G services was because it made an application to us to do this. This decision was taken after conducting a thorough assessment of how competition might be affected."
On 23 January, the UK operators began bidding in an auction that will decide how new spectrum to support 4G is shared out. The auction was originally supposed to take place in 2012.
Matthew Howett, an analyst at market research firm Ovum, said Ofcom's consultation was welcome, but he questioned whether it would help operators launch 4G services quicker.
Most would be unlikely to use the spectrum they already own for those services in the "short term", he said,
"They would first need to be cleared of their existing use through a process of refarming that would probably take years rather than months," he said. "So the spectrum that is currently being auctioned by Ofcom will most likely be used for Vodafone, O2 and Three's initial deployment of 4G services."