Rising supply and falling demand is pushing down rents.
New Cotality analysis of MBIE data shows the national median rent dropped 0.3% in the year to May.
That's the first time the rent has dropped in more than 15 years.
Aspire Property Management's Managing Director Mike Atkinson told Mike Hosking housing supply is increasing at the same time incomes are falling in real terms.
He says there's also been a huge drop-off in net migration, with fewer people coming into the country.
However, there could be some good news on the way for landlords.
Atkinson says things should pick up over summer, when migration typically increases.
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