UN chief Antonio Guterres called Monday for international engagement with the Taliban to avert an economic collapse in Afghanistan, insisting aid could be used as leverage to improve human rights.

Speaking to journalists on the sidelines of a donor conference for the conflict-torn country, Guterres said: "It is impossible to provide humanitarian assistance inside Afghanistan without engaging with the de facto authorities.

"It is very important to engage with the Taliban at the present moment."

Humanitarian needs were already towering before the Taliban swept into power on August 15, said the UN secretary-general, urging the international community to "find ways to allow for an injection of cash in the Afghan economy".

It was vital, he said, to allow the economy to breathe and avoid a collapse that would have "devastating consequences" for Afghanistan and the wider region.

'Strong programme'

Monday's conference, aimed at raising more than $600 million, had raised some $1.1 billion in pledges of various types of support for Afghanistan and its neighbours by the time half the speakers had been heard.

But Guterres said it remained unclear how much of that would go towards the UN appeal.

Even before the Taliban takeover, some 40 percent of Afghanistan's GDP was drawn from foreign funding, and half of the population was dependent on humanitarian aid.

With mass displacement inside the country and winter approaching, aid agencies have cautioned that malnutrition and even starvation is looming for many.

Guterres reiterated the United Nations' commitment to remain in Afghanistan and deliver desperately needed aid.

A number of countries have said they do not want to engage with the Taliban directly because of concerns over rights abuses.

But Guterres said this was the wrong approach.

"I don't think that if the de facto authorities of a country misbehave, the solution is to do a collective punishment to their people," he said.

Instead, he suggested direct engagement with the Taliban, including on aid deliveries, could help push Afghanistan's new authorities towards more respect for human rights.

"It's important to launch a strong programme of humanitarian aid and to use it as a leverage in order to (engage) with the Taliban (and) make the human rights dossiers move forward," he said.

But Guterres stressed that "humanitarian aid will not solve the problem if the economy of Afghanistan collapses."

"My appeal is for mechanisms to be found to make sure that we don't let the economy of Afghanistan collapse."