The Public Safety Alliance, an advocacy group of public safety agencies and supporters, will "strongly oppose" any efforts to auction the D block, Moore said. The draft legislation also doesn't give priority funding from spectrum auctions to the deployment of the public safety network, he said.

The FCC, in an auction that ended in early 2008, attempted to sell the D block, on the condition that the winner build a nationwide network to be shared between public safety agencies and commercial users. The auction failed to generate the FCC's minimum bid, and the D block has been in limbo ever since.

In February, President Barack Obama to public safety agencies and allocate more than US$10 billion to build a nationwide network. But Republican subcommittee members said Friday they have to consider the U.S. government's US $1.5 trillion budget deficit when deciding whether to auction the D block.

"Any plan to allocate this prime spectrum opens a $3 billion hole in the nation's budget," said Representative Greg Walden, an Oregon Republican and subcommittee chairman.

Other witnesses questioned the Republican proposal's ground rules for how the FCC could auction spectrum voluntarily turned over by U.S. television stations. The proposal ties the FCC's hands on pricing, on relocating TV stations and on reserving some of the spectrum for unlicensed uses such as Wi-Fi, said Peter Cramton, a consultant and an economics professor at the University of Maryland.