Hekmatyar wants to create an alliance with the Taleban
"We are in negotiations with the Taleban, in Kabul, Kandahar, Baraki, Jalalabad, but also in Peshawar [in Pakistan] to create a united front. [Taleban leader] Mullah Omar is being kept up to date on the progress," he told French news agency AFP.
"We are also in contact with the Northern Alliance forces, with all those in the interior and exterior of Afghanistan, who are involved in the conflict."
No Taleban collapse
He did not explicitly name which opposition leaders he had contacted, but added: "The object of these discussions was to rally all those who want to defend our country.
"It is not a question of already distributing ministerial posts [in a post-Taleban government], or of who will control the region."
He claimed Hezb-e-Islami forces were still numerous in Afghanistan, especially in the provinces of Nangarhar, Lugar, Jalalabad and Bamian, but denied that he wanted to eventually take control of the country.
"The leaders of the Northern Alliance had hoped for the collapse of the Taleban in the first days, even the first hours, of the American attacks," he said.
"They have now understood that it was not that easy."
Kabul besieged
An ethnic Pashtun, Hekmatyar fought against Soviet occupation in the 1980s and then against his Tajik rival, the late Ahmed Shah Masood, when the communist government collapsed in 1992 and both factions entered Kabul.
Hekmatyar, who was excluded from the new Mujahedin government by President Burhanuddin Rabbani, lay siege to Kabul causing tens of thousands of civilian deaths.
Within two years he and Rabbani were forced to flee as the Taleban descended on Kabul.
Hekmatyar is yet another key Afghan figure to enter the fray. Before the start of the military campaign, he told the BBC that the US had no right to attack Afghanistan.
He said the Americans were wrong to blame Osama Bin Laden for the attacks in New York and Washington, and warned that he would oppose them.
The news follows unconfirmed reports that another former Mujahedin commander, Abdul Haq, has been executed by the Taleban after being caught in the east of Afghanistan.