US Republican lawmakers are voicing growing alarm over a possible deal with the Taliban that would see five militants transferred from Guantanamo as part of peace talks on ending Afghanistan's insurgency.

The criticism comes after President Barack Obama's administration acknowledged negotiations for a potential transfer of five inmates from the prison at the US naval base at Guantanamo Bay, Cuba to Qatar in exchange for the Taliban renouncing violence.

Mike Rogers, chairman of the House Intelligence Committee, called it a "bad idea" that would jeopardize battlefield gains by US-led troops in the war in Afghanistan.

"If this happens, we have crossed a red line that we will never be able to get back. It is a serious doctrinal change for the United States government," Rogers told a hearing with intelligence chiefs.

The possible prisoner transfer has been portrayed by officials as a "confidence-building" measure to clear the way for peace talks to end the 10-year war.

The Obama administration insists no final decision has been made and that talks with the Taliban are at a preliminary stage, but Rogers and other Republicans are demanding the White House abandon the approach.

Citing insurgent attacks on local Afghan leaders, Rogers said "negotiating with people who are associating with this level of violence is very concerning, given that they haven't even slowed down their political assassinations during the course of those very negotiations. Very, very disturbing."

Rogers accused the administration of ignoring intelligence reports that made clear the Taliban and its allies are committed to seizing back power, as well as a 2009 assessment that deemed the five Taliban prisoners too dangerous for release.

At a Senate hearing Tuesday, Republican Saxby Chambliss questioned intelligence leaders about the risks of transferring the five, who reportedly include Mullah Khair Khowa, an interior minister under the Taliban's former regime.

A 2009 review by US agencies concluded the five detainees were too dangerous to be released but could not be prosecuted, National Counterterrorism Center director Matthew Olsen told the hearing.

"It appears from these reports that in exchange for transferring detainees who had been determined to be too dangerous to transfer by the administration's own Guantanamo review task force, we get little to nothing in return," Chambliss said.

"Apparently, the Taliban will not have to stop fighting our troops and won't even have to stop bombing them with IEDs (improvised explosive devices)," he added.

US officials have said the transfer, if carried out, would be in exchange for the Taliban renouncing ties with international terrorism, effectively a public break with Al-Qaeda.

At Wednesday's House hearing, CIA Director David Petraeus said his spy agency had carried out a more recent assessment of the possible consequences of transferring the Taliban inmates.

The evaluation looked at different scenarios with various "mitigating measures" designed to prevent the inmates from returning to insurgent violence, he said.