Some Auckland property owners are considering renting out their homes when they move overseas and it's contributing to the slowdown of the rental market.

New migration data shows in the year ended August there was a record net loss of 56,100 New Zealand citizens, with just over half headed to Australia.

Migration gains also fell to the lowest level since early 2023.

Barfoot and Thompson general manager Samantha Arnold said the data is being reflected in housing in the Auckland region.

She said there is a lot more stock than there are tenants.

"We're seeing owners move overseas wanting to rent their properties out, but we've also got tenants moving overseas as well so there's a slight over supply.

"It's not a huge boost but it's definitely noticeable and when you talk to people on the ground they're nodding their head and saying yes we're seeing it. It may be like a handful in a region but there's definitely a movement towards that."

New Barfoot and Thompson data shows the average rent in Auckland was 4.8 percent higher than a year ago - the first drop below 5 percent all year.

Arnold said annual rent increases for the region typically sit between 5 and 8 percent.

She said homeowners are also waiting to see what happens with interest rates before they put their houses on the rental market, which means both owners and tenants are moving less adding to rents easing.