Swimming: Kiwi sensation Erika Fairweather smashes Olympian's 43-year-old national record

New Zealand's oldest swimming record is no more.

Erika Fairweather from Dunedin smashed the 400m freestyle mark for 15 year olds set by the great Rebecca Perrott in winning the age group title in Wellington on Saturday.

Fairweather, a member of Dunedin's Neptune Swim Club, recorded 4min 12.10s, way ahead of Perrott's 4min 14.7s.

Her record-breaking swim would have earned her the bronze medal in the 1976 Olympics in Montreal - where Perrott recorded the time to become New Zealand's youngest Olympian.

Erika Fairweather shaved over two seconds off the 400m freestyle record. Photo / Facebook

The gold was won in that race by East German Petra Thumer in world record time.

It is Fairweather's 11th long course age title and she also holds six short course ones. She also broke the 100m, 200m and 800m marks, and won eight golds.

"It was beyond what I was hoping for, so I'm very happy," she said.

Fairweather will look to carry on the fine tradition of Kiwi 400m swimmers. New Zealand's best swimmer of recent times has been the now-retired Lauren Boyle, the Commonwealth Games gold medallist, world championship bronze medallist and Olympic finalist in that distance.