While the Residential Tenancies and Rooming Accommodation Act 2008 does not make specific reference to mould, it does outline specific requirements in relation to the standard that a rental property must be maintained.
If mould becomes present in a rental property, the tenant should notify the property manager/owner as soon as they are aware of the mould issue.
Deciding who is responsible for cleaning mould and repairing any resultant damage depends on how the mould appeared in the first place.
If mould is a result of problems with the property (for example, a leaking roof, or water damage caused by leaking pipework), it is the property manager/owner’s responsibility to address the mould and make any necessary repairs.
If the tenant has caused the mould to appear (for example, by allowing steam to build up in a bathroom without proper ventilation and/or regular cleaning), they are responsible for cleaning it and paying for any damages that the mould has caused.