Properties on the website's rental index have risen by an average of $50 in the last year, bringing the national median rental price to $650.
"While it's not the biggest annual increase we've ever seen, it is unusual to see it this high in March," Trade Me property sales director Gavin Lloyd said in a statement.
"We'd normally expect to see the market cool slightly as we exit summer and start heading into the colder months."
The increase amounted to an extra $2600 per year for most New Zealanders, he said.
The steepest increase was in the Manawatū-Whanganui region, which was up 10 percent to $550.
In the same period, rentals in Wellington didn't shift at all, staying at $650.
Auckland saw a 6.2 percent increase and remained the most expensive city with an average weekly rent of $690.
Southland saw a 9.3 percent increase - the second largest nationwide - but remained the cheapest region at an average of $470.
Demand was down and supply has risen for the second month, the index also showed.
Compared with the same time in 2023, there were 22 percent fewer inquiries and 3 percent more properties available in March.
While there was still some way to go before supply caught up with demand, rents might stablise or even fall, Lloyd said.
Meanwhile, apartments, townhouses and units were in demand across the motu, together jumping to a record-breaking average of $580 per week in March, 8.4 percent more than the same time last year.
Rents were growing faster outside the main city centres. Lloyd said it showed Kiwis were willing to trade a bit of space for a desirable location.
