Ngetich, who also broke the women-only 10 km world record last year, pushed to the front from the outset on a sunny morning in the Danish capital and led till the end, finishing 50 seconds before compatriot Veronica Loleo, who came in second.
The previous record was set by Peres Jepchirchir, another Kenyan, when she won the World Half Marathon title in 2020.
The overall women's half-marathon world record is held by Ethiopia's Letesenbet Gidey, who clocked 1:02:52 in 2021.
Sunday's win was the latest major title this year for the 25-year-old Ngetich, who also won the team half marathon in Copenhagen and the World Cross Country Championships in January.