Barack Obama's half-sister says she is proud of the way the Democratic candidate has carried himself during his presidential campaign and she believes that, if elected, he will help the United States "look forward" to a brighter future.

Maya Soetoro-Ng told CTV's Question Period that her half-brother has run an "exceptional campaign" that has hit the key issues and has avoided being "unreasonably aggressive" in tone, she said.

"He has, I think, been very focused on what is important and he has not succumbed to tactics that might dishonour his character," she said in a phone interview from Honolulu, Hawaii.

Her half-brother has stuck to his principles and has put forth a "benevolent and clear" vision for the country that he hopes to lead, she said.

Soetoro-Ng also spoke of the times she spent with Obama when they were growing up.

"I've often said in this campaign that it matters a great deal that Barack is someone who took care of his younger sister, even when he was a teenager," she said. "He's someone who really enlarged my perspective."

She said Obama took an interest in her education and taught her the importance of community and volunteer work.

"What we're seeing here is a man of great character, a man who is going to help us make the right decisions, who is going to broaden our perspective, who is going to thrust open the window and help us get some clarity of vision and to look forward," she said.

"He is very earnest in wanting to make sure that the United States is the best version of itself that it can possibly be," she added later. "And I think he's going to do that."

Obama visited his half-sister in Hawaii last month when he spent some time with his ailing grandmother, 86-year-old Madelyn Dunham.

At the time, he said he did not know if his grandmother would live to see the election.

Soetoro-Ng, who has been taking care of Dunham, said the visit was a special one.

"We are certainly glad that Barack had a chance to come here," she said. "It was very important for him to spend some time with her and to let her know how much she has meant to him personally and to this family."