International donors led by India and China pledged around $3 billion to rebuild quake-devastated Nepal on Thursday, as the country's premier vowed "zero tolerance" of corruption and said all aid would go to victims.

Nepal says it needs around $6.7 billion to recover from the April disaster, which killed more than 8,800 people, destroyed nearly half a million houses and left thousands in need of food, clean water and shelter.

At a meeting of foreign donors on Thursday, India's Foreign Minister Sushma Swaraj pledged $1 billion to finance reconstruction, while regional rival China promised 3 billion yuan ($483 million) in grant assistance.

Nepal's two giant neighbours have historically vied for influence in the Himalayan nation and both were heavily involved in post-quake rescue and relief efforts.

Additional pledges of $600 million from the Asian Development Bank, $260 million from Japan, $130 million from the US, $100 million from the EU, $58 million from Britain as well as an earlier announcement of up to $500 million from the World Bank have now taken total assistance to around $3 billion.

The government wants all aid to be channelled through a new state body, raising concerns among some international donors that bureaucracy and poor planning will hamper reconstruction.

Prime Minister Sushil Koirala urged delegates to "work with us, the government of Nepal" and vowed "zero tolerance toward corruption".

"I assure you that we will (leave) no stone unturned in ensuring that the support reaches the intended beneficiaries," he said as he opened the one-day meeting in Kathmandu.

The UN says some 2.8 million people still require humanitarian aid, including access to food, sanitation and medical care, with its initial $423 million emergency appeal only generating $153 million in funding, even as Kathmandu prepares to rebuild.

Nepal -- one of the world's poorest countries even before the disaster -- desperately needs assistance to rebuild homes, schools and hospitals destroyed or damaged by the April 25 earthquake and a strong aftershock on May 12.

One in 10 people are homeless and the country's already weak economy has been hit hard, with annual growth forecast to fall to just three percent, the lowest in eight years.

'NOTHING LEFT'

In Kathmandu, victims of the disaster, still sheltering under tents, welcomed news of international assistance.

Sunita Shrestha, a 28-year-old housewife whose home collapsed in the quake, said, "if foreigners have come to help us then the Nepal government cannot step back...they will have to do something".

"We have nothing left...I am hopeful but not expecting much since the government has done nothing for us so far," Shrestha told AFP.

As pledges rolled in, participants said it was crucial to ensure the money was spent well.

"Money will be important for building back a more resilient Nepal... but it's not just about money," said World Bank president Jim Yong Kim in a video message to delegates.

"Just as important is how these funds are spent."

The international community pledged several billion dollars in aid to Haiti after a catastrophic earthquake struck the Caribbean nation in January 2010.

But the pledges yielded little tangible progress as donors delayed implementing projects due to concerns over corruption and political instability, leaving thousands living in temporary shelters five years on.

"Follow-up is extremely important -- when pledges are made, the government formulates its plans accordingly and if the money doesn't come, it throws everything out of gear," said Poonam Khetrapal Singh, the World Health Organization's (WHO's) regional director for South-East Asia.

"We have seen that happen in previous cases with devastating results so I think we will lose our credibility as members of the donor community if we don't act on our promises," Singh told AFP on the sidelines of the conference.

As donors vowed to deliver on pledges, officials urged Kathmandu to lay out a clear roadmap to recovery.

"Now that the pledges have been made, it is the government's responsibility to develop projects and programmes," said UN Under-Secretary General, Gyan Chandra Acharya.

"Once it has decided on the projects, it can call on donors and ask them to deliver early on funding," Acharya told AFP.

Nepal regularly fails to spend annually budgeted funds -- including foreign aid -- on projects because of red tape.