A vegetation fire across the road from a Whanganui petrol station was sparked when a helium balloon floated into powerlines.
Whanganui station officer Shane Dudley said a helium balloon had floated up into the powerline, popped and then dropped down onto the grass below, setting it alight.
Emergency services arrived the scene on London St opposite Z service station at about 2.15pm on Monday where a section of mesh covered grass was on fire.
"We just had to wait for the power to be isolated and make sure everyone was safe before we could proceed," Dudley said.
A witness said: "I just saw it hit the power lines, drop and create this blue spark. It sort of looked like fireworks."
Police cordoned off London St, from Grey St to Victoria Ave, as Fire and Emergency NZ extinguished the small blaze.
Power to nearby homes and businesses in central Whanganui was lost for a time and also affected traffic lights on nearby streets.
Countdown Victoria Ave and Pak'nSave lost power requiring an emergency generator for their frozen/chilled food.