Jacob said the trend indicated fewer people were standing up for themselves and enforcing their rights.
It also required a lot of time to pursue a Tenancy Tribunal case, he said.
"For a lot of working people who have to work more and more in order to afford the roof over their heads it's not necessarily a viable option."
Wellington and Hutt Valley community lawyer Machrus Siregar said the decreasing number of cases reflected an issue of supply and demand for rentals.
"A lot of tenants don't want to kick up a fuss because they don't feel like they have a lot of options in the current market."
Siregar said although more tenancy complaints were landing on his desk than ever before, these were less likely to be escalated to the Tenancy Tribunal.
Rainey Collins associate commercial lawyer Louisa Joblin said renters are acutely aware Tenancy Tribunal decisions are publicly available and landlords may take these decisions into account when considering the suitability of tenants.
"The recent stories of "blacklisting" of tenants on social media are concerning, and it is a positive step that the Privacy Commissioner is looking into the issue."
Joblin noted in recent years protections for both tenants and landlords have been improved in recent years through legislation including the Healthy Homes Standards and amendments to the Residential Tenancies Act 1986.
"These changes have meant that landlords are being held to a higher standard, and tenants' rights are met without the need for them to enforce their rights in the Tribunal. It has also meant that the quality of rental housing available is generally improved."
She also said Tenancy Tribunal resources have improved over the past decade, making information and advice more accessible.
