Another family say they too have had their property splattered by what they believe is human excrement dropped from a plane.

John Thompson contacted the Herald after reading about the Burns family in Karaka, who were hit twice by excrement they suspected came from an aeroplane.

The Burns had the substance ESR-tested the second time and the results revealed that it was, in fact, human waste.

Mr Thompson, his wife Darrell and their three sons have had to clean up the mess three times in the past three years. The family refer to the hits - which have happened once each year since 2008 - as "shit bombs".

"The first one was the worst," Mr Thompson said. "The south side of our house was completely and utterly caked. You can tell it's come from a high point because of the splatter ... it was well-splattered."

In the second incident, in 2009, the east side of the house was splattered and last year a small part of the home was covered, as well as the driveway and one of the family's vehicles. Each incident happened during the night and when no one was outside.

Like the Burns, Mr Thompson said they contacted the Civil Aviation Authority, but were told to prove that it had come from a plane.

He did not pursue the matter as, like the Burns, he felt as if he was being fobbed off by authorities.

Asked whether it could have been avian excrement, Mr Thompson said that that would be hard to believe, given the strong smell of human waste.

The Civil Aviation Authority yesterday said that it had received about 30 complaints of similar happenings in 2003, but had no record of Mr Thompson's call.

The authority's inquiries with the Department of Conservation had, however, found that they were all attributed to ducks in the area.

Spokeswoman Emma Peel said yesterday that the authority did not question the results of the ESR tests taken from Mr Burns' property, but maintained that it could not have come from a plane as there were no aircraft flying in the area at the time.

She said that aircraft did not have a "casual release latch" that could easily be removed in mid-air.

"There are latches and valves going from the toilet to a main holding tank to more valves and another latch. It's not something easily emptied."