She won the Transvulcania ultra-marathon in convincing style at the weekend.
The race was in the Canary Islands, an archipelago of Spain.
Frost (32) won the 83.3km race in 8hr 10min 41sec to beat the previous women's record she set in 2012 by 50sec.
Frost is a member of the Salomon team and finished just under 10min in front of Maite Mayora (La Sportiva), who finished in 8hr 20min 29sec.
Uxue Fraile (Vibram) was third in 8hr 48min 01sec.
Frost, who is based in Annecy in the French Alps, was frustrated by a series of injuries last year and this was her first highly competitive race for more than 12 months.
Frost started at a fast pace and had an early lead over main rival Emilie Forsberg, of Germany.
Forsberg had a heavy fall early in the race and badly injured her hand and arm and was forced to withdraw after 24km when she was 2min behind Frost.
At this stage, Frost was 6min ahead of her own course record but she slowed on the long descent and was only a few seconds faster than the record after 68km.
Frost gained ground on the flatter conditions over the last 19km to comfortably beat her old record.
It was a fitting way for Frost to celebrate her 10th year in the ranks of professional mountain runners.
In 2012, Frost broke the race record by a massive 1hr 48min 32sec.
The men's race was won by Luis Alberta Hernando (team Adidas) in 6hr 55min 41sec.
It was 1min 32sec slower than the previous record set by Kilian Jornet (Spain) last year.
The Transvulcania is one of the hardest ulta-marathon mountain races It has an elevation gain of 4415m and an elevation loss of 4110m.
The race has been held on the Island of La Palma since 2009.
Frost will now have a rest for a couple of weeks and then compete in a race in the French Alps.
Frost was one of Otago's most promising distance runners, especially over road and cross-country, and competed for the Hill City club before becoming a mountain running professional.
