Every tenant is entitled to sublet or assign a tenancy, unless the landlord has been exempt from the provision of the Residential Tenancies Act 1995 (SA) [s 74]. An exemption applies where the landlord is a registered community housing organisation [s 74(4)].

A tenant may only sublet or assign the tenancy with the landlord's written consent, but a landlord's consent cannot be unreasonably withheld [s 74(1)-(2)]. It would be unreasonable to withhold consent for a discriminatory reason under the Equal Opportunity Act 1984 (SA) [s 74(3)].

A landlord cannot demand or receive a fee or payment for giving consent to the assignment or sub-letting of a lease. To do so would be an offence for which the maximum penalty is $20,000 (expiation fee $1,200).

Assigning or subletting all or part of any premises without the landlord’s consent is invalid unless the South Australian Civil and Administrative Tribunal SACAT determines that consent is not required [s 74(5)]. If a tenant believes a landlord has unreasonably withheld consent to assign or sublet a premises, they can apply to SACAT for a determination that consent is not required [s 74A].

The relationship of head tenant (who enters into the original tenancy agreement with the landlord) and sub-tenant (who enters into a tenancy agreement with the head tenant) is, in essence, the same as that of landlord and tenant. The sub-tenant pays rent to the head tenant for the right to exclusive occupation of part or all of the premises for which the head tenant has been granted a similar right by the landlord. A sub-tenancy must be for at least one day less than the head tenant's own term, otherwise it is regarded as an assignment of the tenancy agreement.

It is important to remember that under the original tenancy agreement, and for as long as the sub-tenancy or assignment lasts, the head tenant is responsible and liable to the landlord for the rent and the condition of the premises. The sub-tenant is responsible only to the head tenant and a sub-tenancy agreement automatically terminates on the termination of the main tenancy agreement. If a sub-tenant damages the property the landlord will have an action against the head tenant or assignor, who can then take action against the sub-tenant for rent owing or for the damage to the premises for which the landlord has a claim.