Former British prime minister Gordon Brown on Thursday called for the Taliban government's treatment of women and girls in Afghanistan to be declared a crime against humanity.

Brown, the UN special envoy on global education, denounced the Taliban authorities for "systematic brutalisation" of women and called for the International Criminal Court to investigate.

"I think the evidence is absolutely overwhelming," Brown, who was in office from 2007-10, told BBC radio.

"Complete discrimination against women, banned from university, banned from schools, banned from public places, banned from any activities where they're walking on their own.

"Required to wear a particular dress -- not even just the normal dress of a Muslim but very particular requirements on dress -- and all those being prosecuted, including the leader of the NGOs, who are forcing the pressure for girls' rights, now in prison.

"So this is systematic brutalisation of women and girls," he said.

Brown's comments come days ahead of the second anniversary of the Taliban takeover in Afghanistan on August 15, 2021.

Since seizing power, the Taliban government has barred girls and women from high schools and universities, banned them from parks, funfairs and gyms, and ordered them to cover up in public.

Women have also mostly been barred from working for the UN or NGOs, and thousands have been sacked from government jobs or are being paid to stay at home.

Brown said the Taliban authorities' treatment of women was "probably the most heinous, the most vicious, the most comprehensive abuse of human rights that's taking place around the world today".

"And it is systematically being inflicted on millions of girls and women across Afghanistan.

"That's why it's seen as a crime against humanity, and it's right for the International Criminal Court, which has responsibility for dealing with crimes against humanity, to both investigate and to prosecute those people who have been responsible."

The former Labour Party leader said he also wanted to see sanctions against the "individuals responsible for this policy".

"The European Union has done it, but America and others can do it," he added.