A Kiwi scientist is encouraging New Zealanders to bet on the sperm of which hihi, or stitchbird, is quickest, in a fundraising effort to look after the songbird's population.

Otago University researcher Helen Taylor has taken sperm samples from four different locations around the North Island to see which area produces the fastest swimmers.

Taylor told Mike Hosking it's an important measure, because concerns are rising that a dwindling population could lead to inbreeding and, in turn, infertility.

"The numbers are reasonably low and we know that they've have these drastic reductions in population size which can lead to issues with their genetics and can increase problems like inbreeding."

It costs $10 to make a bet on which sperm is the fastest, with all proceeds going towards sustaining and building new hihi populations.

LISTEN ABOVE AS HELEN TAYLOR SPEAKS WITH MIKE HOSKING