Defending champion Hannah Kearney of the US is favored to retain her women's moguls Olympic crown while Canada's Alex Bilodeau is tipped for more glory in the men's event as freestyle skiing gets under way on Thursday.

In the women's aerials competition, China's Li Nina will be looking to make it third time lucky after taking silver at the past two Games in Turin and Vancouver and China's men will also be a major threat.

No 1-ranked Kearney, the 2005 and 2013 world moguls champion, has dominated the sport in recent years but said the competition is getting tougher.

"Everyone gets faster and better every year, but I'd like to think I'm included in that," said the 27-year-old.

Kearney said that being Olympic champion had not changed her approach for Sochi.

"I know everyone wants to beat me even more. There's no place to go at the top, except to fall or stay there," she said.

The American will be wary of the challenge from Canada's Justine Dufour-Lapointe - the youngest of three sisters competing in the event.

Top-ranked Bilodeau, 26, took silver at last year's world championships in Norway to go with his Olympic gold in front of home fans in 2010. He will face fierce competition from fellow Canadian Mikael Kingsbury, who won last year's world title.

Australia's 2006 Turin moguls gold medalist Dale Begg-Smith - who won silver in Vancouver - is hoping to turn back the clock following a three-year sabbatical from the sport.

"I have been paying attention to the other guys in the team, saw them improving and you just get the edge when you see the Olympics coming up," he said.

China's Li, 31, missed much of 2013 through injury but came back to win World Cup aerials events in China and Canada.

She will face fierce competition from compatriot Xu Mengtao, the 2013 world champion, and China's Cheng Shuang.

The reigning Olympic champion is Australia's Lydia Lassila.

China is also strong in the men's aerials, with reigning world champion Qi Guangpu and Liu Zhongqing, who topped the 2013-14 World Cup standings, among the medal hopefuls.

Freestyle skiing and skeleton are the only sports in which all previous gold medals have been won by different athletes.

Alexei Grishin of Belarus will attempt to defend his aerials title and Swiss skier Michael Schmid will be aiming for his second gold medal in men's ski cross.

Other names to watch out for include world champion Fanny Smith of Switzerland in the women's ski cross and Canada's world champion Kaya Turski in the women's slopestyle.