Emerging pistol shooter Siobhan Nicholls has claimed Australia's first Olympic Games quota spot on offer at the Oceania Championships.

Nicholls took the first of 14 quota spots available at the titles in Brisbane by winning the women's 25m pistol.

Competing at her first senior international competition, the 22-year-old upstaged Australia's dual Olympian Elena Galiabovitch in the final, 25-23.

"I wasn't uber-confident," said Nicholls, who last year was in Shooting Australia's development pathways program.

"I actually (was) a little bit nervous about the final.

"We had a lot of wind ... everyone had a pretty challenging match and definitely not ideal conditions."

Galiabovitch will have another chance to earn a quota for Australia in the 10m air pistol.

South Australia's Alison Heinrich took the bronze, completing an Australian sweep of the medals ahead of three New Zealand shooters.

"It's an amazing opportunity to be competing against two amazing women that are Elena and Alison," Nicholls said.

"I'm so grateful to stand beside them. I just used it as an opportunity to put the pressure on myself to see what I could do."

Australia hope to claim the majority of quotas available at the Oceania Championships, ahead of selecting the shooting team next year.