Nationwide rental prices increased nearly 10 percent in the year to the end of June.

But in some regions it's leapt even higher - prices in Hawke's Bay have gone up 20.4 percent; Bay of Plenty's up 16.4 percent; Manawatu-Whanganui's up 14.2 percent; and Northland's up 12.8 percent.

Professor Graham Squires from Massey University's real estate analysis unit talks to Māni Dunlop about what's influencing the hikes.