Representatives from dozens of countries are gathered in Tokyo, where they are expected to pledge billions of dollars in support for Afghanistan.
International donors will pledge $16 billion in aid for Afghanistan over the next four years in hopes of stabilising the country after most foreign combat troops return home.
A US diplomat said the money will come with conditions to ensure it does not fall victim to rampant Afghan corruption and mismanagement.
Kabul can cover only a third of the $6bn it spends each year, not counting security costs, and has for a long time been heavily dependent on aid.
But many, both inside and outside the country, fear that once the US and its allies withdraw their troops in 2014, the country could be left to fend for itself.
Afghan President Hamid Karzai, who is in Tokyo along with US secretary of state Hillary Clinton and United Nations chief Ban Ki-moon, has called for pledges of $4bn a year in civilian aid.
"In these past ten years, with help from the international community, we have made remarkable progress toward healing the scars of conflicts and destruction," Karzai said. "And we are laying down a new path for people to realise their aspiration of a peaceful and prosperous and democratic country."
According to the World Bank, spending on defence and development by foreign donors accounted for more than 95 per cent of Afghanistan's GDP in 2010-11.
A security conference in Chicago in May, involving the countries of the NATO-led coalition, adopted a plan to provide $4.1bn in annual security aid in coming years. The focus in Tokyo will be on development.
In an interview with the Asahi Shimbun newspaper published on Friday, the Japanese foreign minister, Koichiro Gemba, said he hoped the conference would result in pledges worth at least $3bn a year. But he warned the money would come with strings.
"(Kabul) must improve its governance capacity, including eradicating corruption," he said.
On Saturday, Gemba said donors will stump up more than $16bn for four years to 2015, adding Japan would provide up to $3bn over five years, in addition to $1bn for Afghanistan's neighbours.
"This scale of pledge will satisfy the fiscal gap that the World Bank and the Afghan government have said would be needed for the development of the country," Gemba said.
His announcement came hours after Clinton said the United States had designated Afghanistan a major non-NATO ally, giving it special privileges. Clinton announced the move, which provides a long-term framework for security and defence cooperation, during a brief visit to Kabul where she had a breakfast meeting with Karzai.