WASHINGTON, US - BARACK Obama will buck tradition and accept the Democratic presidential nomination in August at a 75,000 capacity football stadium, the party said on Monday, in what will likely be a spectacular photo-op.

The Illinois Senator's formal prime time speech is being switched to Invesco Field, home of the Denver Broncos American football franchise, from a smaller indoor hockey and basketball arena hosting the rest of the convention.

Mr Obama attracted massive and enthusiastic crowds during his victorious primary campaign against Hillary Clinton, and party officials said the new venue would again help fire up grass-roots activists countywide.

'The Democratic Party is nominating a true change candidate this August, and it is only fitting that we make some big changes in how we put on the Convention,' said Democratic National Committee chairman Howard Dean.

'Barack Obama's campaign for change has inspired millions of Americans and brought people into the political process who might never have been involved,' said Democratic convention co-chair Kansas Governor Kathleen Sebelius.

'This change in the convention program will allow thousands of first-time participants a chance to take part.'

'I can't think of a better convention finale for our nominee who has made reaching out to voters a hallmark of his campaign.'

Mr Obama's speech, on August 28, will be his most prominent chance to sell his vision of hope and change to Americans.

He will be aiming to upstage his own performance, at the Democratic convention in 2004, when as a virtual unknown, he shot to political prominence with an electrifying speech.

The Democratic National Convention in Denver, Colorado runs from August 25 to 28.

Republicans will officially nominate their White House pick, Senator John McCain in Minneapolis, Minnesota between September 1 and 4. -- AFP