A meeting of finance ministers and central bankers from Britain, Canada, France, Germany, Italy, Japan and the United States called on Afghanistan's donors to provide the country with grants.
During a meeting in Florida on Saturday, they also urged Afghan authorities to stamp out opium production.
"We will provide assistance that will produce visible and measurable results before June as part of our long-term commitment to the country," the ministers vowed, albeit without putting a dollar figure on their ambitions.
The pledge came after the international community was sharply criticised recently for failing to meet its commitments in the Asian country.
However, the G7 said that it will support Afghan education "by building schools, training teachers and providing textbooks", and will back a project aimed at doubling the country's percentage of paved roads in six years.
Their statement urged institutions to help companies that want to do business in and with Afghanistan as it fosters "a climate where the private sector can flourish".
The ministers and central bankers said they would work with Afghanistan's creditors to ensure that the country's debt situation is "sustainable", and with bilateral donors who will be encouraged "to provide as much assistance as possible in the form of grants".
"We will provide assistance that will produce visible and measurable results before June as part of our long-term commitment to the country"
G7 ministers' statement
They acknowledged all such initiatives face risks from internal insecurity and pledged to back reforms to the police and the legal system, as well as the disarmament, demobilisation and re-integration of former combatants.
"We recognise that opium production poses a major threat to security, economic growth and reconstruction in Afghanistan," the G7 added.
"We call upon the international community and the Afghan authorities to join together to eliminate opium production."
US President George Bush last Monday asked Congress for $1.2 billion in reconstruction aid for Afghanistan, which would match the $1.2 billion in assistance the administration earmarked for 2004.
That figure was increased by $300 million to around $1.5 billion by Congress.
But while the new US cash injection was welcomed in the aid community, it fell well short of what both aid groups and the Afghan government believe is necessary to rebuild the country.
Kabul puts the reconstruction bill at around $30 billiion over the next five years.
The G7 pledge came after a recent report by Human Rights Watch condemned the international community for shortchanging Afghanistan.
The rights organisation said despite grandiose promises, the world has been stingy with Afghans.
"In a shocking display of political short-sightedness, countries that have declared war on terror and on drugs... have failed or refused to marshal the resources necessary to combat the resurgence of armed groups and drug lords in Afghanistan," report author Sam Zia-Zarifi wrote.
"In a shocking display of political short-sightedness, countries that have declared war on terror and on drugs... have failed or refused to marshal the resources necessary to combat the resurgence of armed groups and drug lords in Afghanistan"
Human Rights Wwatch report
HRW said many of those who control the purse strings in the international community have failed to listen to calls for assistance.
"Despite the call for $20 billion over five years, the international community has pledged only $7 billion... Of this $7 billion sum, the international community has to date actually provided only $4 billion.
"Only a third of this amount has made its way to Afghanistan over the last two years. And of that amount, only some $200 million has resulted in completed projects."
Zia-Zarifi added that in the absence of the Taliban, which in some years managed to stop nearly all poppy production, opium cultivation has again exploded in Afghanistan.
"Much of this trade and the money it generates is under the control, or at least the influence, of various major and minor military commanders, who use this money to increase their military capability and gain independence from the central government and any international troops working with them."