Sarah Atkin (Lower Hutt) continued her domination of New Zealand women's downhill mountain biking in Dunedin on Saturday.

Atkin, who won the first race in the New Zealand Mountain Biking Cup in Queenstown last week, gained her second win on the tough Signal Hill course by the convincing margin of 41.64sec.

Atkin was in a class by herself when she won the elite women's race in 4min 36.39sec from Alanna Columb (Queenstown, 5min 18.03sec) and Amy Laird (Christchurch, 5min 18.93sec).

She showed her experience, adapting to the difficult conditions on the Signal Hill course.

"It was very slippery," she said. "It went hard this morning but the rain made it slippery on top."

She found the hardest part of the course was off the corners on the tree roots at the top of the track.

"I got off my bike and walked over the roots because I kept slipping out." Atkin has the potential to become the next New Zealand female to win a world downhill mountain bike title.

She has demonstrated her potential over the last two years by finishing fifth at the world junior championships in 2010 and 2011.

She began mountain biking when she was a pupil at Hutt Valley High School nearly four years ago and found she was a natural at the sport.

"I started because I wanted something to do," she said. "I enjoy the challenge of being on my bike and I like the people in the sport."

She reached the podium in an international event for the first time when she won the Oceania title last year.

Atkin won her first New Zealand open title last year and she will be hard to stop this year after winning the first two races of the series.

Columb (20), who works in a tourism company, had an impressive ride to finish second because she has only been competing in downhill mountain biking for six weeks.

Dan McCombie (Dunedin) won the men's under-19 title in 3min 45.17sec from Nelson pair Leo Sandler (3min 45.52sec) and Reece Potter (3min 46.01sec).

His younger brother, Josh McCombie, won the men's under-17 title in 3min 48.99sec.

Leighton Kirk (Karitane) won the senior men's title in 3min 23.19sec, Derek Winwood (Nelson) the masters men's title in 3min 32.43sec, and Adrienne Hooper (Waitakere City) the open women's title in 4min 25.62sec.

Carlos Wilson (Dunedin) won the under-15 boys title in 4min 35.17sec.