* Access could help reconciliation efforts
* Baradar could be key broker
* Pakistan may be willing to play bigger peace role (Adds comment, detail)
By Abdulaziz Ibrahimi and Michael Georgy
KABUL/ISLAMABAD, Aug 12 (Reuters) - Afghan officials have held secret talks with the Taliban's former second in command who is in detention in Pakistan in a move which could help rekindle stalled peace talks with the insurgents, according to senior officials from both countries.
Afghan officials have often seen Pakistan as a reluctant partner in attempts to broker talks with the Taliban but its decision to grant access to Mullah Abdul Ghani Baradar may signal Islamabad's willingness to play a more active role.
Rangin Spanta, the national security adviser to Afghan President Hamid Karzai and an architect of peace-building efforts, said an Afghan delegation had met Baradar in Pakistan two months ago.
Baradar has been in detention since he was captured in a joint operation by the CIA and Pakistani intelligence agents in the Pakistani city of Karachi in 2010.
"We have met Mullah Baradar," Spanta told Reuters in Kabul. "Our delegation has spoken to him to know his view on peace talks."
Afghan officials have publicly been demanding access to Baradar, the Taliban's top military commander until he was captured, but Spanta's revelation shows preliminary contact has already been made.
Rehman Malik, Pakistan's interior minister, also said that Pakistan had granted Afghan officials access to Baradar.
"They had access at the required and appropriate level," Malik told Reuters.
"We are fully cooperating with Afghanistan and whatever they are asking for the peace process, for developing peace in Afghanistan. We are giving every kind of help."
Pakistan is seen as crucial to stability in Afghanistan as most foreign combat troops look to leave the country in 2014, given close political and economic ties and because militant sanctuaries straddle the mountainous border.
Baradar was the main day-to-day commander responsible for leading the Taliban campaign against U.S. and NATO troops, plotting suicide bombings and other attacks.
He was the right-hand man to reclusive Taliban leader Mullah Mohammed Omar, who gave him the nickname Baradar (brother), providing him with great influence and prestige in Taliban circles.
CRITICAL TO RECONCILIATION?
Afghan officials hope Baradar could play a key role in any negotiations to end the war, acting as a go-between with Taliban leaders including Omar.
Afghan and U.S. officials have publicly acknowledged little success in efforts to re-start peace talks, which the Taliban suspended after accusing U.S. officials of failing to honour confidence-building promises.
That setback refocused attention on nascent efforts by the Afghan government to open its own channels with insurgent intermediaries, despite the fact the Taliban publicly say they will not talk to what they deem an illegitimate "puppet" government.
Karzai, at a recent donors' meeting in Japan, also appealed to Germany to act as a go-between to revive talks, in a second track to contacts with Taliban leaders in Pakistan.
A Western official said Pakistan's decision to grant access to Baradar would bolster hopes of greater collaboration between the two countries, but the Afghan government would only be fully satisfied if Baradar was repatriated to Kabul.
"It's a step in the right direction, but there's still a number of steps to go," the official said.
Although Afghan officials may be pinning hopes on Baradar, it is unclear what influence he may have over a complex insurgency after spending years in detention.
Pakistan and Afghanistan agreed last month to resume regular talks on Afghanistan's peace process, with the new Pakistani prime minister promising to help arrange meetings between Afghan and Taliban representatives.
Afghanistan is known to want access to Taliban leaders belonging to the so-called Quetta Shura, or council, named after the Pakistani city where they are believed to be based.
Kabul believes they would be the decision-makers in any substantive negotiations aimed at ending a war in its eleventh year.
Pakistan has consistently denied giving sanctuary to insurgents and says no Taliban leaders are in Quetta.
The Afghan government has established some contacts with the Taliban, who have made a strong comeback after being toppled in 2001, but there are no signs that full-fledged peace talks will happen any time soon.
U.S. diplomats have also been seeking to broaden exploratory talks that began clandestinely in Germany in late 2010 after the Taliban offered to open a representative office in the Gulf emirate of Qatar, prompting demands for inclusion from Kabul.
(Additional reporting by Matthew Green in Islamabad and Rob Taylor in KABUL; Editing by Robert Birsel)