US President Barack Obama says it may take a couple of weeks or a couple of months to reach a deal to end Washington's battle over spending cuts.

The president spoke after meeting briefly with congressional leaders at the White House on $85 billion in automatic spending cuts that go into effect today.

Mr Obama says the cuts are "dumb and arbitrary" and he blamed them on Republicans in Congress.

The cuts are kicking in after the White House and congressional Republicans failed to overcome bitter disagreements and come up with a better plan to tackle the country's $11.7 trillion debt.

The warring sides spent this week assigning blame rather than seeking a way out and rival Democratic and Republican measures to modify the cuts failed in the senate yesterday.

The automatic spending reductions are part of a law passed two years ago and designed to be so off-putting to both Democrats and Republicans as to force a compromise.

The immediate impact of the cuts on the public was uncertain and the administration pulled back on its earlier warnings of long lines developing quickly at airports and teacher job losses. It is expected to be a fiscal speed-bump on the road to economic recovery that is otherwise looking good.

The cuts would carve 5% from domestic agencies and 8% from the Pentagon between now and October 1 but would leave several major programmes alone, including the Social Security pension scheme, the Medicaid health care programme for the poor and food stamps.