The problem was becoming so bad the SPCA had created a waiting list as there wasn't enough space to take in the animals.
But Helen Hodgson, from Barfoot & Thompson, said the decision from the majority of landlords to ban pets was costing them.
Just 14 per cent of the 12,000 Auckland rentals on its books allowed for pets.
Of those, on average they charged an extra $20 a week to pet-owing tenants.
Hodgson said there were other options for landlords other than ruling out pets, such as a pet bond and a clause which outlines responsibility for pet-related repairs.
There were also other landlord benefits to allowing pets.
Barfoot & Thompson's data found renters with pets gave landlords better stability because they stayed seven months longer than non-pet owners.
"Tenants with pets are often happy to pay a little more for a good rental home and many know how hard it is to find a pet-friendly property so when they find one, they stay longer," Hodgson said.
"Reducing tenant turnover also saves on costs associated with moving, for tenants and landlords."
Aucklander Sarah Fleming has been desperately looking for a pet-friendly home for three weeks, with no luck.
The cat owner has trawled 300 properties and only 18 would negotiate on pets - and to make matters worse her flatmate has two dogs.
"Pets are so important to people's emotional well-being so it is not an option for us to not have one."
