Cairns placed fourth in the women's heat, but was the first Pacific nation to cross the line which was all she needed to book her place.
Cairns' coach, Gavin Elmiger, who watched the results live from Auckland said he was ecstatic with Cairns results.
"She didn't realise initially until they said 'hey look you've qualified' and she was like 'what?' She couldn't believe it, so now there's a possibility that one of the Cook Island girls may qualify for the games as well, so it's exciting."
