outside Afghanistan as he feared that his government would be frozen out of any negotiations.
The militants refuse to have direct contact with Karzai, saying he is a puppet of the United States, which supported his rise to power after the military operation to oust the Taliban in 2001.
But, with NATO-led combat troops due to withdraw from Afghanistan by the end of 2014, Karzai agreed to the proposed Taliban office in Qatar and is expected to firm up the plan with the emir of Qatar on Sunday.
Any future peace talks still face numerous hurdles before they begin, including confusion over who would represent the Taliban and Karzai's insistence that his appointees are at the centre of negotiations.
"We will discuss the peace process, of course, and the opening of an office for the Taliban in Qatar," presidential spokesman Aimal Faizi told AFP before Karzai left Kabul with several senior members of his government.
"If we want to have talks to bring peace to Afghanistan, the main side must be the Afghan government's representatives - the High Peace Council, which has members from all the country's ethnic and political backgrounds," Faizi added.
Negotiating with the hardline Taliban regime that had harboured Al-Qaeda before the 9/11 attacks was for many years an anathema to many countries fighting in the UN-backed coalition against the militants.
But the search for a political settlement became a priority as the insurgency raged on with Taliban leaders able to fuel the violence from safe havens across the border in Pakistan.
Kabul has repeatedly stressed that it would only start talks if the militants broke all links with Al-Qaeda and gave up violence, and Faizi said that any Taliban office in Qatar must be held to strict conditions.
"It can only be an address where the armed opposition sit and talk to the Afghanistan government," he said. "This office can not be used for any other purposes."
The UN this week welcomed news that Karzai would visit Qatar, and issued another call for the Taliban to come to the peace table. "You are Afghans, you care, I assume, about your country, you care about (a) peaceful stable future of the country," Jan Kubis, the UN envoy to Afghanistan, said.
But the Qatar office could mean little if the Taliban refuse to negotiate with Karzai or the government-appointed High Peace Council. "The opening of the Taliban office in Qatar is not related to Karzai, it is a matter between the Taliban and the Qatar government," spokesman Zabihullah Mujahid told AFP. "If Karzai visits, it is not our concern. Our representatives who are already in Qatar won't see or talk to him."
Neighbouring Pakistan, which backed the Taliban's 1996-2001 rule of Afghanistan, is seen as key to any workable peace deal and it has expressed support for the Taliban office in Doha.
But cross relations have worsened sharply in recent weeks, with Kabul accusing Islamabad of wrecking efforts to end the bloody 11-year insurgency.
The Islamist militants broke off tentative contacts with the US in Qatar a year ago after the failure of attempts to agree on a prisoner exchange as a confidence-building measure.