A top U.N. development official said it will take at least five years to rebuild the infrastructure in Afghanistan.

The head of the U.N. Development Program, Mark Malloch-Brown, said the world organization can play a vital role in Afghan redevelopment because of its long history of humanitarian work in Afghanistan.

But he said the U.N. role would be to assist, not direct, the rebuilding efforts. Mr. Malloch-Brown noted that there are now more than 2,000 Afghans working for various U.N. agencies and that large numbers of Afghan refugees will be able to supply skilled labor to the country.

The U.N. official will be attending a meeting on Afghan reconstruction Tuesday in Washington. The meeting, sponsored by Japan and the United States, will be to discuss preliminary plans.

Mr. Malloch-Brown said there is currently no cost estimate, but that the commitment must be sustained. "It is extremely important to get a five-year plan covering recovery and reconstruction, and get as close to "bankable" commitments now for the five years if possible. The real costs come in years three, four, and five. So I am anxious to get an early credible figure that covers the full five years and try to get commitments to that figure from donors.

Although Mr. Malloch-Brown could not estimate the cost of Afghan recovery, he said that there might be some analogy to an international reconstruction program in the African nation of Mozambique. That program cost $6.5 billion.

Plans for rebuilding Afghanistan are contingent on a viable interim government there. Other U.N. officials continue work to organize talks on the subject with a broadly representative group of Afghan leaders.