Bush was briefed by Secretary of State Colin Powell on Powell's tour last week of tsunami-hit countries. The White House said that of $350 million pledged by the US government, $78 million had been spent.
Bush left open the possibility of an increase in US assistance but told reporters he wanted to make sure it was "demand-driven" and to "make sure the money that is available actually achieves a coordinated objective."
Lawmakers and congressional aides have said they expected the Bush administration to increase the financial commitment to the region by as much as threefold to nearly $1 billion -- in an emergency budget request to be submitted to Congress in late January or February.
The emergency budget request for tsunami relief is expected to include extra funding to cover the cost of operating the Pentagon's military assets in the region -- estimated at $5 million to $6 million a day.
"This is one of these projects that is not going to happen overnight. The intense scrutiny may dissipate, it probably will. But our focus has got to stay on this part of the world. We have a duty," Bush said in remarks to US officials overseeing the aid operation.
Talking to reporters in the Oval Office after his meeting with Powell, Bush said relief efforts had begun to shift from saving lives to rebuilding communities.
HARDEST HIT AREA
The Banda Aceh region of Indonesia was close to the epicenter of the Dec. 26 quake and took the biggest hit from the resulting tsunami. The province has accounted for almost all of Indonesia's 104,000 deaths from an epic disaster that has killed at least 156,000 people.
"Now we're in the process of helping to rehabilitate and reconstruct the societies. And the demand is beginning to focus on the Banda Aceh region. That is part of the world that is going to require the most intense effort by the governments around the world," he said.
In New York, former President Bill Clinton announced a joint initiative with the United Nations to raise $45 million to bring safe drinking water and sanitation systems to children and families affected by the tsunami.
Clinton, who was enlisted by Bush along with former President George Bush to lead a nationwide appeal for assistance from the US public, said he was confident of reaching the target, given the world outpouring of support.
Clinton and UNICEF, the UN Children's Fund, are seeking donations for the Tsunami Water and Sanitation Fund to www.clintonfoundation.org and www.unicefusa.org.
Later on Monday Bush was to meet with experts on the extent of tsunami monitoring around the world and whether the United States has sufficient safeguards to alert the country in the event of a similar natural disaster.
Bush was criticized for his initial reaction to the catastrophe when he pledged $15 million in US government assistance to help tsunami victims but has since mobilized government, military and private aid for the victims.
(Additional reporting by Adam Entous in Washington and Larry Fine in New York)