"I'm going to find out over time what went right and what went wrong," George Bush said in reply to criticism that the authorities were too slow to respond.
There was "ample time" for an inquiry, he said, but the priority was helping the Gulf Coast and New Orleans.
Officials in New Orleans have urged its last residents to leave the swamped
city, saying "it is now uninhabitable".
The city's Times-Picayune newspaper has demanded the sacking of top officials
at the US Federal Emergency Management Agency (Fema).
One allegation levelled at Fema is that at the height of the crisis it turned away water and diesel because of bureaucracy.
President Bush is due to meet US politicians from both parties to discuss
the devestating disaster.
"How the different levels of government had reacted to Katrina would
be examined", Mr Bush said, but he refused to "play the blame game".
"We got to solve problems - there will be ample time to figure out what
went right and what went wrong," he said in Washington.
America, he added, had to be sure it could respond properly to another disaster,
whether natural or an attack with weapons of mass destruction.
Stressing his focus on victims, Mr Bush also pledged not to allow "bureaucracy...
to get in the way of getting the job done for the people".
Ex-President Bill Clinton, and his wife, Senator Hillary Clinton, have been among those to call for an inquiry into the handling of Katrina.
Mr Bush also announced that Vice President Dick Cheney would visit Gulf Coast region on Thursday to help assess the government's work.
On both sides of the political divide there is an acceptance of the fact that if the president is seen to have failed personally to provide leadership, then nothing can be salvaged from his second term in office, a BBC correspondent reported.
