An electrical explosion may have sparked a grass fire that scorched the corner of a West Bush Rd farm just after noon on Sunday.
Firecrews were alerted by a resident who heard "a loud explosion" and they arrived just in time to stop the blaze from spreading, said Masterton Station Officer Mike Cornford.
"It's just a little grass fire that's gone through the flax and trees, it started to take off when we got here but we got it under control."
Mr Cornford said because of the noise heard they thought the powerlines overhead may have caused the fire but, upon investigation, they could not see any problems with the lines.
"It might be some form of electrical explosion, Powerco will be having a look.