The United Nations has opened a two-day conference in Geneva today (Tuesday) on organizing and coordinating the four billion dollars of aid that has been pledged for victims of last month's Indian Ocean tsunami.

The conference is bringing together officials from 80 countries -- including 12 directly affected by the disaster.

Andrew Natsios, head of the U.S. Agency for International Development, is representing the United States in Geneva. He told reporters Monday the meeting is aimed at coordinating relief efforts and preparing a long-term recovery plan for affected countries.

The United Nations says it will let independent consulting firm PricewaterhouseCoopers track operations -- to ensure that the aid gets to those in need.

The December 26 tsunami killed more than 150,000 people and left millions homeless.

Indonesian authorities say they will begin regulating the movements of foreign aid workers helping with tsunami relief efforts in Aceh province.

The officials say they are concerned about possible attacks on the workers by forces of the Free Aceh Movement, (GAM) who have been fighting government forces for nearly 30 years.

They say rebels have attacked relief supply convoys and briefly taken a foreign doctor hostage. In a statement the Free Aceh Movement denied the charges and said it will not attack aid workers.

Meanwhile, United Nations relief coordinator Kevin Kennedy tells reporters that international military helicopters and boats are delivering aid to areas of Sumatra's western coast that have previously been cut off. Workers are also rebuilding a road along the Sumatran coast to allow supplies to be delivered by truck.

As immediate crisis relief gives way to longer-term rebuilding efforts, the Indonesian government has permitted at least one relief organization (Mercy Corps) to pay tsunami survivors to clear debris and recover dead bodies. The organization says giving survivors a way to earn money will help the nation's economic recovery.