Latest data from realestate.co.nz shows seven regions including Manawatu/Whanganui, the Central North Island and Taranaki had record high averages for asking prices.
Spokesperson Vanessa Taylor said Covid-19 doesn't seem to have dampened sellers' expectations.
She said demand also remained high, with traffic to the sight on par with February, its peak month.
New listings and total stock were both down nationally in May but those numbers were similar to the last two winters.
Central Otago and the Lakes District had an increase in listings - up 13% - on the same time last year.
Taylor told RNZ's Morning Report programme she was genuinely surprised by the findings.
"There's been a lot of speculation around prices post-lockdown, but what we've seen here is vendors are able to command high prices for their property.
"You can't command a high price for your property if the demand isn't there, and when we look, New Zealanders are still busy."
Taylor said it remains to be seen if house prices will fall.
