Whangarei Citizens Advice Bureau co-ordinator Moea Armstrong said she was surprised by the value of unclaimed bonds.
She said she could understand landlords needing to keep bond money for repairs but questioned why else anyone would forfeit getting their bond back.
Ms Armstrong said the bureau could give information on the bond refund process and provide people with appropriate forms.
The bureau also sometimes heard from tenants in disputes with landlords over whether they should receive their bond back.
MBIE general manager of service support and design Mike West said bonds could remain unclaimed when tenants changed their details without telling the Ministry or moved overseas.
Common reasons for bonds going uncollected included invalid bank account details, returned cheques and not all parties confirming refund details.
He said there was a six-year limit on claiming a bond after a tenancy had ended. Many bonds included in the Ministry's figures had exceeded the six-year period.
Ministry calculations suggested about 40 per cent of unclaimed bonds could be claimed.
Any bonds which had been unclaimed for six years belonged to the Crown.
The name's bond, unclaimed bond:
* Far North: Unclaimed 1389 ($411,923.00). Uncollected: 495 ($117,911.03).
* Whangarei: Unclaimed: 1912 ($543,261.73). Uncollected: 849 ($250,420.55).
* Kaipara: Unclaimed: 315 ($88,416.60). Uncollected: 113 ($29,061.97).