Democrats have launched their case for US President Barack Obama's re-election, looking to draw a sharp contrast with Republican rival Mitt Romney and convince voters that Mr Obama has the more sensible plan for economic recovery.

First Lady Michelle Obama's appearance was the opening night highlight of the three-day Democratic gathering in Charlotte, North Carolina, which concludes with Mr Obama's acceptance speech tomorrow to more than 65,000 supporters in a downtown football stadium.

The convention gives Mr Obama a chance to recapture the political spotlight from Mr Romney and the Republicans, who used their nominating convention last week to attack Mr Obama's economic leadership.

The task for Mr Obama and his allies will be to convince voters disappointed by his first White House term that things will be better the second time around, while portraying the budget-slashing economic remedies offered by Mr Romney and his running mate, Congressman Paul Ryan, as unacceptable alternatives.

Mr Romney and Mr Obama have been running fairly even in opinion polls before the November 6 election, but Mr Obama hopes to get more of a convention bounce in polls than Mr Romney, who gained a few percentage points at most from the Tampa event.