The Housing Authority may have to review the penalty scheme it uses to punish dirty tenants if a second challenge to an eviction under the system succeeds.
No one has been evicted yet under the two-year-old scheme.
A tenant ordered to leave after accumulating 17 points for littering and spitting lodged an appeal with the authority yesterday.
Under the scheme, introduced in the aftermath of the Sars outbreak, tenants are given five demerit points for littering and seven for spitting or throwing objects from a height. Tenants face eviction if they get 16 points within two years.
A family whose tenancy was terminated last October for littering twice and throwing an object from a height had the decision overturned two months later by the authority's appeal panel.
Two other tenants have appeals pending. One faces eviction for keeping a large amount of waste in the flat and the other for littering and spitting.