The Hutt Valley District Health Board is concerned old laboratory forms have been maliciously mailed to the neighbours of four former patients.
Chief operating officer Jill Lane believes someone has had access to confidential laboratory information in 2002 and for some reason is now mailing the forms to former patients at a neighbour's address.
Another five forms have been sent to media, with a note saying they were found in a recycling bin.
Ms Lane says there is nothing to suggest the forms came from a recycling bin.
She says the board is distressed about the matter.
