Police warn residents a group of men posing as professional roof painters are active in the region.
Senior Sergeant Jymahl Glassey said the men had been door-knocking offering to reseal and paint people's roofs.
There have been two complaints - one in Masterton and one in the Hutt Valley - of sub-standard work by the men.
Mr Glassey said the men were targeting the elderly.
He urged people to do a background check on door-knockers before hiring them for any jobs.
