Denver, Colorado - Barack Obama's kids took their turns playing with the convention gavel as their mother was getting oriented on the Democratic gathering's podium Monday morning.

As Michelle Obama, 44, squinted out into the convention hall at the Pepsi Center, trying to envision her much awaited headline speech on the opening night of the Democratic convention later Monday, one of her daughters picked up the gavel and brought it down with a bang.

"I didn't know it would be that loud," quipped Malia Anne, 10, who wore a brown dress with a flower border and a little white sweater.

It was the sort of moment that can endear a candidate's family to voters and boost popularity - a leg-up that Senator Obama, 47, could sorely use. A pair of polls released late Sunday put him in a dead heat with Republican John McCain.

Malia and her sister, Natasha "Sasha", age 7, their long hair in old-fashioned ringlets, frolicked on the podium while a small group of photographers and reporters watched.

Michelle Obama, dressed in black pants and a shimmery green shirt, was all business, ignoring reporters' questions and trying to figure out where she would look and how she would read the monitor during her speech.

But when a Swedish journalist asked if she had a message for the people of Sweden, she flashed a smile and said: "Tell them thank you - and keep us in their prayers."

She also admitted she was "very excited" about her speech on the first day of the four-day event in the Rocky Mountain state of Colorado.

Michelle Obama will be joined Monday evening on the podium by her brother, Craig Robinson, a favourite basketball pal of the candidate's, and the candidate's half sister, Maya Soetoro-Ng, who will try to sculpt a profile of Barack Obama that will re-introduce him to an American public who has seen him on the national scene for only four years.

Senator Edward Kennedy, who had been expected to deliver a videotaped message to the convention because he is suffering from serious brain cancer, could in fact appear in person, reports said.

Michelle Obama, who was initially reluctant to make public appearances when her husband cast his hat in the Democratic ring last year, will also be participating in forums on women and the economy and other issues vital for women voters during the convention week in Denver.

She has become a star attraction of his campaign, even if some of her comments early on drew controversy - such as a remark that she was proud for the first time in her life to be an American after she saw the huge response to Obama in the primary elections.

But during her trial run at the podium, she demonstrated the sort of pressures many working mothers are under, balancing work concerns and her responsibilities to her daughers - and showed her grace despite the distractions of her children.

Little Sasha, dressed in a print dress and maroon sweater, could barely be seen behind the podium - but she also found the gavel and brought it down noisily, getting a huge smile from her mother.

At another point, as Michelle Obama strained to figure out where the teleprompter would be, Malia came to the rescue with the eyes of a 10-year old.

"I'll read it to you," she offered. Mom put her hand on Malia's arm, said "shhhh" and just laughed.