Business confidence has slumped to its lowest level since before the 2013 Federal election, with economic weakness and political uncertainty both playing a role, according to the latest National Australia Bank survey.

NAB's monthly business survey for February found that sentiment had slumped 3 index points, to 0, in the last week of February, despite fresh stimulus from the first Reserve Bank of Australia cut to the cash rate in 18 months.

The declining sentiment comes despite steady business conditions. Credit:Michele Mossop

The survey period also coincided with feverish speculation about the governing Coalition's leadership.

The poor reading, below the long-run average and the worst since just before voters dismissed the unpopular Gillard-Rudd Labor government in September 2013, reflects the mood across most industries and business sectors, according to NAB.