Guterres said he was ready to speak with the Taliban himself "when it is clear with whom should I speak, for what purpose." For now, UN officials in Kabul have been in close contact with the Taliban, he added.
"It's very important for the international community to be united, for all members of the Security Council to be united, to use the only leverage that exists, which is the interests of the Taliban for legitimacy for recognition," he said.
He said a common front in dealing with the Taliban could push them to form an inclusive government, respect human rights, continue to allow evacuations from Kabul and prevent Afghanistan from becoming a safe haven for terrorism.
"We've all heard the purported assurances from the Taliban, that the rights of women and girls will be respected. What we hear from women on the ground does not bear this out," Ireland's UN ambassador Geraldine Byrne Nason, a member of the UN Security Council, told reporters on Thursday.
"This is linked very much to the question of the legitimacy of any government," she said.
Under Taliban rule between 1996 and 2001, women could not work and girls were banned from school. Women had to cover their faces and be accompanied by a male relative when they left home.
The heads of UN agencies and international aid groups appealed on Thursday for more humanitarian funding for Afghanistan as they pledged to stay, warning that they were at least $800 million short of what was needed.
"This is not the time to abandon the Afghan people, the Inter-Agency Standing Committee (IASC), made up of at least 18 UN agencies and international aid groups, said in a statement.
At the start of the year, half of Afghanistan's population - more than 18 million people - needed help, they said. A UN appeal for $1.3 billion to reach 16 million people this year with humanitarian aid is only 37 per cent funded.
"Those needs have risen sharply because of conflict, drought and Covid-19," they warned.