The tiny stoat is seen darting from side to side as the bird sprints after it.
It's not known if the weka managed to catch the stoat, with Predator Free NZ revealing the pair disappeared back into the bush.
"Just your typical West Coast," says the man filming.
"That's brilliant - get it weka get it!"
Twitter users took to the post to poke fun at the incident.
"They eat mice too yes? Great predator control agents!" said one woman.
"Can we aerial drop weka into problem pest areas?" wrote another.
The weka species is in decline due to predators such as stoats, cats, dogs and ferrets.
The weka is a protected species in New Zealand.
