Contrary to popular belief, Christchurch's worst hoarders may not be risking their own health.

Shocking living conditions have come to light as agencies across Christchurch consider how best to cope with extreme collectors.

Canterbury Medical Officer of Health Alistair Humphrey says accumulating large numbers of possessions isn't as unsanitary as some might think.

"I have seen people who live in houses where they don't have a functioning toilet, where they're surrounded by cats and they are sick as a butcher's dog."

Canterbury psychiatrist Matthew Croucher says while hoarding is defined as a psychiatric disorder, that's not always the case.

"In our society people do need to be free to make really bad decisions about themselves.

"It is not clear that everyone that hoards is mentally unwell."

Matthew Croucher says mental health services and health-care workers need to take each case carefully on its own merits.