When Maryam went shopping in Kabul this week after several weeks cooped up at home, the Afghan mother was shocked to discover food prices had doubled -- or even tripled -- at the market's well-stocked vegetable stalls.

"It's very expensive, it's clearly visible," the 52-year-old, who lost her job after the Taliban returned to power in August, told AFP.

On Wednesday, a United Nations report said Afghanistan and its population of roughly 40 million people have suffered an "unprecedented fiscal shock" since the Taliban takeover and the decision by the international community to withdraw billions in humanitarian aid.

The report predicts an economic contraction of around 20 percent of GDP "within a year, a decline that could reach 30 percent in following years".

"It took more than five years of war for the Syrian economy to experience a comparable contraction. This has happened in five months in Afghanistan," United Nations Development Programme (UNDP) Asia Director Kanni Wignaraja told AFP.

Another UN source said that such a situation was "never seen before. Even... Yemen, Syria, Venezuela don't come close."

For decades now Afghanistan's economy has been undermined by war and drought.

But it was propped up by international aid, which represented 40 percent of Afghanistan's GDP and financed 80 percent of its budget.

That was frozen when US-led international forces left the country and the Taliban took control. 

"The sudden dramatic withdrawal of international aid is an unprecedented fiscal shock," Wignaraja said.

For Maryam, trying to buy food in the Kabul market, it spells potential disaster.

Her husband is ill, and cannot work. They have seven children. Under the previous government, she was a civil servant, supporting the family with her salary.

But the Taliban sent women home, only allowing certain female civil servants -- mainly those in education and health -- to return. They have been vague about whether women will be allowed to work in the future. 

For now, Maryam no longer has an income. 

"I have eight mouths to feed, eight people to clothe at home, everything is expensive, and for the moment it seems impossible for me to find another job," she says, not counting herself.

Palliative

Added to this are the Western economic sanctions taken against the Taliban, including the freezing of $9.5 billion in assets of the Afghan central bank, which can no longer intervene to support the economy. 

Afghan banks have been distributing money only in small amounts, with withdrawals limited to a maximum of $400 per week.

The economy is slowing down and unemployment is soaring. According to the UN, 23 million Afghans, more than half the population, are threatened by famine this winter. 

"Afghanistan is in a humanitarian and development crisis that is becoming graver and needs to be immediately addressed to save lives," says the UNDP report, which estimates that $2 billion in emergency aid is needed just to bring the entire population back up to the poverty line. 

If nothing is done, hard-won progress made by international aid in key areas such as education, health, gender equality, access to drinking water, and employment could all be lost, it says. 

The UN agency fears the possible collapse of two key sectors: the banking system and energy, which would plunge the country into darkness. 

In Doha, where the Taliban and the Americans are negotiating this week, the Taliban have again asked the Americans to release frozen funds to allow the economy to recover.

Washington has not responded to these requests, and has urged the Taliban to respect human rights and to give women and girls access to employment and education. 

Depriving women of paid employment could drive GDP down by up to five percent, UNDP said, calling their jobs "vital to mitigate the economic catastrophe". 

In addition, there is a loss in consumption -- women who no longer work no longer have a salary and can no longer buy as much as before to feed or equip their homes - which could reach $500 million per year, according to the UNDP. 

Afghanistan "cannot afford to forfeit this", Wignaraja said, adding that young Afghan women must be allowed a post-secondary education they can work and contribute to the economy later.